An Update on Screening Strategies for Gestational Diabetes Mellitus: A Narrative Review

Figures & data

Figure 1 The literature search and selection process.

Table 1 Screening for GDM in Early Pregnancy

Author, Year/Country (Ref.)	Design	Subjects (N)	Study Population	Timeframe Early Testing (Weeks)	GDM Diagnosis Criteria	Comparison	Main Results
Observational studies
Bartha, 2002/Spain^Citation16	Retrospective cohort study	424	Women with GDM	First antenatal visit (early)	50g GCT followed by, if abnormal, a 3h 100g OGTT/GDM diagnosis if ≥2 values abnormal (≥.5.8, 10.6, 9.2, 8.1 mmol/L)	Earlier vs later (24–28 weeks) screening	Early glucose intolerance screening with a GCT could avoid diabetes-related complications in women diagnosed with GDM
Riskin, 2009/Israel^Citation32	Retrospective study	6129	Singleton pregnancies >24 weeks in mothers without ODIP or FTFPG ≥5.8 mmol/L	<13 weeks	50g GCT followed by, if abnormal, 3h 100g OGTT at 24–28 weeks/CC criteria and GCT ≥11.1 mmol/L	FPG categories (<4.2, 4.2–4.4, 4.5–4.7, 4.8–5.0, 5.1–5.2, 5.3–5.5 and 5.6–5.8 mmol/L)	Higher FTFPG in early pregnancy increased the risk of adverse pregnancy outcomes
van Leeuwen, 2010/the Netherlands^Citation40	Prospective cohort study	995	Singleton pregnancies in women without ODIP <20 weeks	<20 weeks	50g GCT and RPG at 24–28 weeks followed by 2h 75g OGTT if RPG ≥6.8 mmol/L or 1h ≥7.8 mmol/L/WHO 1999 criteria	50g GCT vs RPG	Use of a clinical prediction model is an accurate method to identify women at increased risk for GDM, and could be used to select women for additional testing for GDM
Teede, 2011/Australia^Citation41	Retrospective study	4276	Singleton pregnancies	12–15 weeks	Two-step method: GCT followed by, if abnormal, a 2h 75g OGTT at 28 weeks/ADIPS criteria	Derivation (used to develop a simple predictor scoring tool that specified GDM risk based on identified clinical risk factors) vs validation group	The risk prediction tool, derived from risk factors in early pregnancy, enables simple identification of women at an increased risk of developing GDM
Zhu, 2013/China^Citation34	Retrospective cohort study	14,039	All pregnant women without ODIP	First antenatal visit (<24 weeks)	2h 75g OGTT at 24–28 weeks/ MOH China criteria (fasting, ≥5.10 mmol/L; 1 h, ≥10.00 mmol/L; and 2 h, ≥8.50 mmol/L)	6 FPG groups (<4.1, 4.1–4.59, 4.60–5.09, 5.10–5.59, 5.6–6.09, 6.10–6.99 mmol/L)	Only 30.3% of women who had a FPG of ≥5.1 mmol/L still had a FPG of ≥5.1 mmol/L at 24–28 weeks
Alunni, 2015/US^Citation20	Retrospective cohort study	2652	Singleton pregnancies in women without ODIP	≤24 weeks	Early screening: (1) HbA1c 5.7–6.4% or FPG 5.1–6.9 mmol/L at ≤24 weeks, (2) one abnormal value on a 2h 75g OGTT at 24–28 weeks if normal early screening Standard approach: 1h 50g GCT followed by a 3h 100g OGTT/CC Criteria	Early screening vs standard two-step ACOG approach	Implementing early screening for GDM gave no significant difference in neonatal outcomes
Hong, 2016/US^Citation21	Retrospective cohort study	569	Singleton GDM pregnancies with ≥1 indication for early screening (GDM or macrosomia in a prior pregnancy or obesity)	<20 weeks	1h 50g GCT followed by a 3h 100g OGTT if the former was ≥7.5 mmol/L/CC criteria	Early (<20 weeks) vs routine (>24 weeks) screening	Early GDM screening was not associated with a decreased risk of adverse perinatal outcomes
Sweeting, 2017/Australia^Citation39	Retrospective cohort study	3098	High risk women	<24 weeks	Universal testing at 24–28 weeks with 2h 75g OGTT or 50g GCT and, if positive, a subsequent OGTT/ADIPS criteria	Early GDM (<24 weeks) vs standard GDM (≥24 weeks)	HbA1c >5.9% early in pregnancy identified an increased risk of LGA, macrosomia, C-section, and hypertensive disorders in standard GDM
Mañe, 2017/Spain^Citation35	Prospective multi-ethnic cohort study	1228	Singleton pregnancies in women without ODIP	First trimester	Two-step approach: 50g GCT followed by, if abnormal, a 3h 100g OGTT at 24–28 weeks/NDDG criteria	HbA1c ≥5.9% vs 5.9–6.4%	Early HbA1c ≥5.9% identified women at high risk of adverse pregnancy outcomes independently of GDM diagnosis later in pregnancy
Benaiges, 2017/Spain^Citation36	Retrospective analysis of a non-randomized prospective cohort	1158	Women with a singleton pregnancy without ODIP	<12 weeks	Two-step method: 50g GCT followed by a 3h 100g OGTT if the former was positive/NDDG criteria	First trimester HbA1c of <4.8% vs 4.8–5.5% vs ≥5.6%	HbA1c in early pregnancy lacks sensitivity/specificity for use as diagnostic test, but could be useful in simplifying the diagnostic algorithm for GDM
Hosseini, 2018/Iran^Citation22	Prospective population-based cohort study	929	Singleton pregnancies	6–14 weeks	Universal screening with FPG for ODIP and early GDM at 6–14 weeks. 2h 75g OGTT at 24–28 weeks/IADPSG criteria	Normal pregnancy vs early-onset GDM (6–14 weeks) vs late-onset GDM (24–28 weeks)	Early-onset GDM was associated with poorer pregnancy outcomes
Ryan, 2018/UK^Citation18	Retrospective clinical audit of a prospectively maintained database	576	High risk singleton pregnancies	11–13 weeks	FPG/ 2h 75g OGTT/SIGN 2010 thresholds	Routine vs early screening	Early screening improved the pregnancy outcomes, such as emergency C-section, macrosomia and neonatal hypoglycemia
Bianchi, 2019/Italy^Citation19	Retrospective study	290	High risk women	16–18 weeks	2h 75g OGTT (and FPG)/IADPSG criteria	Early (16–18 weeks) vs standard (24–28 weeks) screening	Similar short-term maternal-fetal outcomes in both groups
Boe, 2019/US^Citation37	Retrospective cohort study	4144	Women without multiple gestations and second deliveries	First antenatal visit (<24 weeks)	HbA1c and/or 3h 100g OGTT/HbA1c ≥ 6.5% (ODIP) vs 5.9–6.4% vs <5.9% and CC criteria	Early HbA1c vs CC testing	Early HbA1c as an isolated test could not replace routine CC testing for GDM because of poor sensitivity
Punnose, 2020/India^Citation38	Retrospective cohort study	2275	Singleton pregnancies in women without ODIP	First trimester (before 13 6/7 weeks)	One-step 2h 75g OGTT at <24 weeks (in case of risk factors) or at 24–28 weeks/IADPSG criteria	HbA1c <5.2% vs 5.2–5.5% vs ≥5.6%	Early HbA1c is an independent GDM predictor in Asian Indian women but lacks sensitivity and specificity for use as a diagnostic test
Benhalima, 2020/Belgium^Citation42	Multi-centric prospective cohort study	1843	Singleton pregnancies without ODIP and history of bariatric surgery	6–14 weeks	Non-fasting GCT and 2h 75g OGTT at 24–28 weeks/IADPSG criteria	Accuracy of the developed prediction model using clinical and biochemical risk factors in early pregnancy vs two validated models (van Leeuwen and Teede)	This prediction model for GDM had a moderate accuracy and could identify women at risk for GDM before or in early pregnancy
Cosson, 2020/France^Citation15	Retrospective study	523	Women with singleton pregnancy and without ODIP and bariatric surgery	<22 weeks	FPG or 2h 75g OGTT/ IADPSG criteria	Immediate care vs no immediate care for early fasting hyperglycemia	Treating women with early fasting hyperglycemia, especially when FPG is ≥5.5 mmol/L, may improve pregnancy outcomes
Liu, 2020/China^Citation17	Prospective cohort study	522	Singleton pregnancies	18–20 weeks	2h 75g OGTT/IADPSG-2015 guidelines	4 groups: NGT (no GDM diagnosis), EGDM (GDM in only early OGTT), LGDM (GDM in only standard OGTT) and GDM (GDM diagnosis in both OGTTs)	Early GDM diagnosis at 18–20 weeks is associated with adverse outcomes
Benhalima, 2021/Belgium^Citation33	Multi-centric prospective cohort study	2006	Singleton Pregnancies without ODIP and history of bariatric surgery	6–14 weeks	Non-fasting GCT and a 2h 75g OGTT at 24–28 weeks/IADPSG criteria	FPG ≥5.1–5.5 mmol/L in early pregnancy vs FPG <5.1 mmol/L in early pregnancy	Group with increased FPG in early pregnancy had significantly more NICU admissions
RCTs
Osmundson, 2016/US^Citation27	RCT	83	Women with singleton pregnancy without ODIP, with HbA1c 5.7–6.4%	<14.0 weeks	2h 75-g OGTT at 26–28 weeks/IADPSG and California Sweet Success Guidelines	Usual care vs early treatment for GDM with diet, BG monitoring, and insulin as needed	Early treatment did not significantly reduce the risk of GDM except in non-obese women
Hughes, 2018 (ongoing)/New Zealand^Citation24	RCT	47	Women with singleton pregnancy without ODIP, with HbA1c ≥5.9–6.4%	<14.0 weeks	2h 75h OGTT/New-Zealand criteria	Standard care vs early intervention in pregnancies complicated by prediabetes	First results expected in 2021
Simmons, 2018 (ToBOGM pilot study)/Australia^Citation25	RCT	79	High risk women with singleton pregnancy	<20.0 weeks (4–19.6 weeks)	2h 75g OGTT/IADPSG criteria	Women with booking GDM receiving immediate (clinical referral or ongoing treatment) vs deferred (no) treatment vs women without booking GDM (‘decoys’)	More NICU admission in the early GDM group with a tendency for more SGA but less LGA
Simmons, 2018 (ToBOGM study protocol)/International^Citation28	RCT	4000	High-risk women with singleton pregnancy	<20.0 weeks (4–19.6 weeks)	2h 75g OGTT at 24–28 weeks/2014 ADIPS criteria	Intervention (immediate treatment) vs control (no treatment) vs decoys (NGT but undergo all procedures) vs non-active (NGT and records reviewed postnatal)	First results expected mid-2021
Vinter, 2018/Denmark^Citation30	RCT	90	Obese pregnant women (BMI 30–45 kg/m^2) with singleton pregnancy	12–15 weeks	2h 75g OGTT/IADPSG Criteria	Lifestyle intervention vs standard care	Lifestyle intervention was not effective in improving obstetric or metabolic outcomes
Roeder, 2019/US^Citation31	RCT	157	Women with hyperglycemia (HbA1c 5.7–6.4% and/or FPG 5.1–6.9 mmol/L) and a singleton pregnancy without ODIP	≤15.0 weeks	2h 75g OGTT at 24–28 weeks/IADPSG criteria	Early pregnancy vs 3rd trimester treatment of hyperglycemia	Treatment in early pregnancy did not improve maternal or neonatal outcomes significantly
Harper, 2020/US^Citation29	RCT	922	Obese women (BMI ≥30 kg/m^2) without ODIP and history of bariatric surgery	14–20 weeks	Two-step method: 1h 50g GCT followed by a 3h 100g OGTT/CC criteria	Early GDM screening (14–20 weeks) vs routine screening (24–28 weeks)	Early GDM screening in obese women did not reduce the composite perinatal outcomes, such as macrosomia, C-section and shoulder dystocia
NCT03523143 (TESGO study) (ongoing)/Taiwan^Citation26	RCT	2068	Singleton pregnancy without ODIP	18–20 weeks	2h 75g OGTT/IADPSG criteria	Early screening group (18–20 weeks) vs standard screening group (24–28 weeks)	Results expected beginning of 2021

Abbreviations: GDM, gestational diabetes mellitus; GCT, glucose challenge test; OGTT, oral glucose tolerance test; FTFPG, first trimester fasting plasma glucose; CC, Carpenter and Coustan; FPG, fasting plasma glucose; RPG, random plasma glucose; WHO, World Health Organization; ADIPS, Australasian Siabetes in Pregnancy Society; MOH, Ministry of Health; HbA1c, hemoglobin A1C; ACOG, American Congress of Obstetricians and Gynecologists; LGA, large-for-gestational age; C-section, caesarian section; NDDG, National Diabetes Data Group; ODIP, overt diabetes in pregnancy; IADPSG, International Association of the Diabetes and Pregnancy Study Groups; SIGN, Scottish Intercollegiate Guidelines Network; NGT, normal glucose tolerance; EGDM, early-onset gestational diabetes; LGDM, late-onset gestational diabetes; NICU, neonatal intensive care unit; RCT, randomized controlled trial; BG, blood glucose; SGA, small-for-gestational age; BMI, body mass index; TESGO, The Effect of Early Screening and Intervention for Gestational Diabetes Mellitus on Pregnancy Outcomes.

Table 2 Current Guidelines for Screening and Diagnosis of GDM

Guideline, Year	Range	One-Step	Two-Step	OGTT Criteria	OGTT Time	Risk Factors List	Screening in Early Pregnancy
IADPSG, 2010	Global	√		≥5.1 (fasting), ≥10.0 (1h) and/or ≥8.5 mmol/L (2h)	24–28 weeks	√	FPG ≥5.1mmol/L in early pregnancy is diagnosed as GDM
WHO, 2013	Global	√		IADPSG	Any time		Criteria apply for the diagnosis of GDM at any time during pregnancy
FIGO, 2015	Global	√		IADPSG	24–28 weeks or any other time	√	Not applicable due to lack of clear evidence
NICE, 2015	UK	√		≥5.6 mmol/L (fasting) or ≥7.8 mmol/L (2h)	24–28 weeks	√	75g 2h OGTT in women with previous GDM as soon as possible after booking
ACOG, 2018	US		√	CC/NDDG	24–28 weeks	√	Consider testing in all women with BMI >25 kg/m^2 (or >23 kg/m^2 in Asian Americans) and with ≥1 additional risk factors
ADA, 2021	US	√	√	IADPSG/CC	24–28 weeks	√	OGTT for high-risk women at the first antenatal visit and classified as T1DM or T2DM

Notes: The OGTT threshold value of IADPSG criteria is 5.1–10.0– 8.5 mmol/L for a 2h 75g OGTT. One or more of these threshold values must be equaled or exceeded for the diagnosis of GDM. The OGTT threshold value of CC criteria is 5.3–10.0–8.6–7.8 mmol/L for a 3h 100g OGTT. The OGTT threshold value of NDDG criteria is 5.8–10.6–9.2–8.0 mmol/L for a 4h 100g OGTT. For CC and NDDG criteria, a diagnosis generally requires that two or more thresholds be met or exceeded, although some clinicians choose to use just one elevated value.

Abbreviations: GDM, gestational diabetes mellitus; OGTT, oral glucose tolerance test; IADPSG, International Association of Diabetic Pregnancy Study Group; FPG, fasting plasma glucose; WHO, World Health Organization; FIGO, International Federation of Gynecology and Obstetrics; NICE, National Institute for Health and Care Excellence; ACOG, American Congress of Obstetricians and Gynecologists; CC, Carpenter and Coustan; NDDG, National Diabetes Data Group; BMI, body mass index; ADA, American Diabetes Association; T1DM, Type 1 diabetes mellitus; T2DM, type 2 diabetes mellitus.

Table 3 One-Step Screening with IADPSG Criteria versus One- or Two-Step Screening with Other Criteria

Author, Year/Country (Ref.)	Design	Subjects (N)	Study Population	Comparison	Main Results
Observational Studies
Agarwal, 2010/UAE^Citation45	Retrospective cohort study	10,283	All pregnant women	Impact of IADPSG criteria on GDM diagnosis compared to ADA criteria	The IADPSG criteria caused a 2.9-fold increase in GDM prevalence (37.7% of all pregnant women with IADPSG criteria vs 12.9% with ADA criteria)
Rajput, 2012/ India^Citation49	Prospective study	607	Pregnant women without ODIP	HbA1c in combination with ADA vs IADPSG criteria for diagnosis of GDM	7.1% were diagnosed as having GDM based on ADA criteria while 23.72% women were diagnosed as having GDM using IADPSG criteria
Benhalima, 2013/Belgium^Citation59	Retrospective cohort study	6727	Singleton pregnancies without ODIP and bariatric surgery	CC criteria (old GDM) vs IADPSG criteria (new GDM) for GDM screening	More women were identified as having GDM using the IADPSG criteria and these women carried an increased risk for adverse gestational outcome compared to women without GDM
Duran, 2014/ Spain^Citation56	Prospective cohort study	3276	Pregnant women without ODIP	One-step IADPSG vs two-step ADA recommended GDM screening	Application of IADPSG screening was associated with a 3.5-fold increase in GDM prevalence as well as significant improvements in pregnancy outcomes
Fuller, 2014/US^Citation50	Pre–post comparison study	812	Pregnant women without ODIP and gastric bypass	One-step (2h 75g OGTT, IADPSG criteria) vs two-step (50g GCT followed by 3h 100g OGTT and CC criteria if GCT ≥7.5 mmol/L)	Despite a 4.7% increase in GDM (from 7% to 11.7%), no differences in delivery or neonatal outcomes and no lower rates of compliance with screening were found when using one-step vs two-step screening
Hung, 2015/Taiwan^Citation58	Before–after retrospective cohort study	6697	Singleton pregnancies >24 weeks without ODIP	One-step IADPSG screening (P2) vs two-step screening (50g GCT followed by 100g 3h OGTT with CC criteria if the GCT ≥7.8 mmol/L) (P1)	GDM incidence increased from 4.6% in P1 to 12.4% in P2. Adoption of the IADPSG criteria led to a significant reduction in maternal weight gain during pregnancy, birth weight, and the rates of macrosomia and LGA
Meek, 2015/UK^Citation60	Retrospective study	25,543	Singleton pregnancies without ODIP	One-step IADPSG criteria vs one-step NICE 2015 criteria for GDM screening	The IADPSG criteria identified women at substantial risk of complications such as LGA who would not be identified by the NICE 2015 criteria
Feldman, 2016/ US^Citation52	Before–after retrospective cohort study	6066	Singleton pregnancies without ODIP	One-step (IADPSG criteria) vs two-step GDM screening (CC criteria)	The IADPSG screening method was associated with a higher rate of GDM (27% vs 17%) but not with a reduction in LGA newborns or cesarean deliveries
March, 2016/ US^Citation53	Retrospective cohort study	235	Singleton pregnancies	One-step (IADPSG) vs two-step (NDDG criteria) GDM screening	The one-step method identified women with at least equally high risk of adverse outcomes as the two-step method
Waters, 2016/North America^Citation48	Secondary analysis of prospectively collected data	6159	Singleton pregnancies without ODIP and fertility treatment	GDM based on CC criteria (also GDM based on IADPSG criteria) vs GDM diagnosed with IADPSG criteria but not CC criteria vs no GDM	Women diagnosed with GDM based on IADPSG criteria had higher adverse outcome frequencies compared with women without GDM
Huhn, 2017/Switzerland^Citation43	Retrospective cohort study	1367 allocated	Women with singleton pregnancy and without ODIP	Two-step screening with 50 g GCT and 2h 75g OGTT (period 1) vs one-step 75g OGTT with IADPSG criteria (period 2)	Introduction of the IADPSG criteria resulted in an absolute increase of GDM prevalence of 8.5% (3.3% in period 1 to 11.8% in period 2)
Adam, 2017/South Africa^Citation44	Prospective cohort study	554	All pregnant women <26 weeks	IADPSG vs NICE vs WHO 1999 vs Western Cape criteria using universal or selective screening	Substantial increase in prevalence of GDM with use of the IADPSG criteria, regardless of universal or selective screening
Luewan, 2018/Thailand^Citation46	Prospective descriptive study	648	Singleton pregnancies excluding those with high risk for GDM	One-step (IADPSG) vs two-step GDM screening based on preference	Prevalence of GDM was significantly higher in the one-step group (32.0% vs 10.3%) without clear evidence of better outcomes
Goedegebure, 2018/the Netherlands^Citation55	Multicenter retrospective cohort study	1386	Singleton pregnancies without ODIP	WHO-2013 (IADPSG) vs WHO-1999 GDM criteria	Using WHO-2013 criteria resulted in earlier GDM diagnosis, less need for insulin treatment and more spontaneous deliveries, but no differences in adverse pregnancy outcomes compared to WHO-1999 criteria
Benhalima, 2018 (Diabetes Care)/Belgium^Citation89	Multicentric prospective cohort study	2006	Singleton pregnancies without ODIP and history of bariatric surgery	Sensitivity and specificity of the 50g GCT in a universal two-step screening strategy for GDM using IADPSG criteria vs a universal one-step screening with the 75g OGTT and IADPSG criteria	The GCT has a moderate diagnostic accuracy in a universal two-step screening strategy with IADPSG criteria; lowering the threshold for the GCT from 7.8 to 7.2 mmol/L would increase sensitivity from 60% to 72% and more than 60% of all OGTTs could be avoided
Pocobelli, 2018/US^Citation54	Before–after cohort study	23,257	Singleton live birth deliveries in women without ODIP	Two-step screening with 50g GCT/FPG test followed by a 3h 100g OGTT vs one-step IADPSG screening	Adopting the one-step approach was associated with an increase in GDM diagnosis (by 41%), and in rates of labor induction and neonatal hypoglycemia, without association with other outcomes including cesarean delivery or macrosomia
Costa, 2019/Belgium^Citation51	Retrospective cohort study	6051	Singleton pregnancies without ODIP	Two-step (50g GCT and 75g OGTT if GCT ≥7.8 mmol/L; CC criteria) vs one-step screening (IADPSG criteria)	GDM prevalence increased from 3.4% to 16.3%, without having a statistically significant impact on pregnancy outcomes
Cade, 2019/Australia^Citation57	Quasi-experimental retrospective study	14,498	Singleton pregnancies without ODIP	1991/1998 ADIPS criteria vs IADPSG criteria	Adoption of IADPSG criteria increased the incidence of GDM by 74% and the overall cost of care without obvious changes in immediate clinical outcomes
Meloncelli, 2020/Australia^Citation47	Pre–post comparison study	124,117	All pregnant women giving birth >24 weeks	Two-step process and 1998 ADIPS GDM diagnostic criteria (in 2014) vs one-step process and IADPSG criteria (in 2016)	GDM diagnosis increased from 8.7% to 11.9%, with no observed changes to measured perinatal outcomes, except for a very small decrease in respiratory distress
RCTs
Mirzamoradi, 2015/Iran^Citation61	RCT	189	Singleton pregnancies without ODIP, with a disturbed FPG or blood sugar at the OGTT	Interventional (one-step screening with IADPSG criteria) vs control group (two-step GDM screening according to ACOG recommendation and CC/NDDG criteria)	Although the treatment of mild GDM (IADPSG) could not significantly decrease severe gestational outcomes, it did significantly reduce the risk of hyperbilirubinemia (OR 0.25) and its subsequent complications
Abebe, 2017 (ongoing)/US^Citation65	RCT	921	Pregnant women from 18 to 28 weeks gestation	50g GCT for all participants, then 1:1 randomization in 75g (one-step, IADPSG) or 100g (two-step, CC) OGTT	No results published yet
Satodiya, 2017/India^Citation62	RCT	1000	Pregnant women without ODIP	Two-step screening (ACOG recommendation, group A) vs one-step screening (IADPSG criteria, group B)	Incidence of GDM using IADPSG criteria was almost doubled (11.8% vs 19.2%), whereas maternal and fetal outcomes were comparable, except in 15.8% women diagnosed as GDM and suffered from hypoglycemia
Fadl, 2019 (ongoing)/Sweden^Citation64	RCT	± 65,000	Pregnant women without ODIP	Intervention (WHO 2013 criteria) vs control group (former Swedish diagnostic criteria)	No results published yet (expected in 2020)
Hillier, 2021/US^Citation63	RCT	23,792	Singleton pregnancies without history of bariatric surgery	One-step (2h 75g OGTT according to IADPSG criteria) vs two-step GDM screening (1h 50g GCT and a 3h 100g OGTT according to CC criteria)	Despite more diagnoses of GDM with the one-step approach (16.5% vs 8.5%), there were no significant differences in the risks of the primary outcomes relating to perinatal and maternal complications

Abbreviations: UAE, United Arab Emirates; IADPSG, International Association of the Diabetes and Pregnancy Study Groups; GDM, gestational diabetes mellitus; ADA, American Diabetes Association; ODIP, overt diabetes in pregnancy; HbA1c, hemoglobin A1C; CC, Carpenter and Coustan; OGTT, oral glucose tolerance test; GCT, glucose challenge test; LGA, large-for-gestational age; NICE, National Institute for Health and Care Excellence; NDDG, National Diabetes Data Group; WHO, World Health Organization; FPG, fasting plasma glucose; ADIPS, Australasian diabetes in pregnancy society; RCT, randomized controlled trial; ACOG, American Congress of Obstetricians and Gynecologists.

Table 4 Selective Screening Based on Risk-Factors versus Universal Screening

Author, Year/Country (Ref.)	Design	Subjects (N)	Study Population	GDM Criteria	Comparison	Main Results
Cosson, 2006/France^Citation77	Observational study	4020	Singleton pregnancies without ODIP	2h 75g OGTT /FPG >5.3 mmol/L (French guidelines) or 2h >7.8 mmol/L (WHO 1999) or both	Selective (risk-factor based) vs universal screening	Universal rather than selective screening for GDM may improve outcomes as universal screening might reduce delay of diagnosis and care
Dahanayaka, 2012/Sri Lanka^Citation75	Cross-sectional descriptive study	405	All pregnant women	IADPSG criteria vs WHO 1999 criteria at 24–28 weeks	GDM diagnosis based on IADPSG criteria (75g OGTT) vs risk-factor based approach (WHO 1999 criteria)	The risk-factor based approach missed 38.9% of GDM cases
Arora, 2013/Thailand^Citation74	Cross-sectional study	593	All pregnant women	1h 50g GCT followed by, if GCT ≥7.8 mmol/L, a 3h 100g OGTT/ACOG (CC) criteria	Risk vs non-risk factor group	21.8% of GDM cases had no risk factor and only 52.8% of pregnant women would enter the screening process when using risk-based screening
Avalos, 2013/Ireland^Citation78	Retrospective cohort study	5500	All pregnant women	2h 75g OGTT at 24–28 weeks/IADPSG criteria	Universal (IADPSG) vs selective GDM screening (Irish vs ADA vs NICE guidelines)	20% (NICE), 16% (Irish), and 5% (ADA) of women with GDM had no risk factor and would have gone undiagnosed
Olagbuji, 2015/Nigeria^Citation81	Prospective observational study	1059	Singleton pregnancies without T2DM	2h 75g OGTT at 24–32 weeks/IADPSG criteria	Universal one-step (75g OGTT) vs risk factor based GDM screening at 24–32 weeks using WHO 1999, WHO 2013/IADPSG criteria	20% of GDM cases would have been undiagnosed if risk-factor based approach was employed
Miailhe, 2015/France^Citation80	Retrospective cohort study	2187	Singleton pregnancies without ODIP	2h 75g OGTT at 24–28 weeks/IADPSG criteria	Universal vs selective (risk factors were those recommended by the IADPSG and French guidelines) GDM screening	Selective screening would have missed 17% of GDM cases diagnosed with IADPSG criteria, but these cases were milder; LGA was associated with GDM in the presence but not in de absence of risk factors
Meththananda Herath, 2016/Sri Lanka^Citation79	Clinic-based cross-sectional study	452	Pregnant women without ODIP	2h 75g OGTT at 24–28 weeks/IADPSG criteria and WHO 1999 criteria	Risk factor based vs universal screening using IADPSG and WHO 1999 criteria	Risk-based screening had a lower detection rate of GDM; however, it reduced the necessity of screening by 20%
Agbozo, 2018/Ghana^Citation76	Prospective blind comparison with a gold standard study	491	All pregnant women ≥15 years without ODIP	WHO 2013 criteria vs NICE 2015 criteria	Selective screening at 13–20 weeks using reagent-strip glycosuria vs RPG vs presence of ≥1 risk factor(s) vs universal screening at 20–34 weeks following the ‘one-step’ approach	Use of risk factors is a better screening tool compared to glycosuria/ RPG because risk factors would miss ±50% of the true positive rate, whereas glycosuria and RPG would miss ±90%
Benhalima, 2019/Belgium^Citation73	Retrospective analysis of prospectively collected data	1811	Singleton pregnancies without ODIP and history of bariatric surgery	2013 WHO criteria vs NICE 2015 (English) guidelines vs Irish guidelines from 2010 vs French guidelines from 2010 vs Dutch guidelines from 2010	Universal screening (75g OGTT) vs selective screening according to NICE 2015 vs Irish guidelines from 2010 vs French guidelines from 2010 vs Dutch guidelines from 2010	By applying selective screening by most European guidelines, about 50% of women would need an OGTT with the lowest number of missed cases (33%) by Dutch guidelines; GDM women without risk factors had higher rates of neonatal hypoglycemia than NGT women
Matta-Coelho, 2019/Portugal^Citation82	Retrospective cohort study	10,443	All pregnant women	2h 75g OGTT at 24–28 weeks/IADPSG criteria	Universal vs risk factor based GDM screening	31.8% would have remained undiagnosed if risk factor based screening was implemented and women with risk factors diagnosed with GDM on universal screening presented worse obstetric and neonatal outcomes

Abbreviations: GDM, gestational diabetes mellitus; IADPSG, International Association of the Diabetes and Pregnancy Study Groups; OGTT, oral glucose tolerance test; WHO, World Health Organization; ADA, American Diabetes Association; NICE, National Institute for Health and Care Excellence; T2DM, type 2 diabetes mellitus; FPG, fasting plasma glucose; LGA, large-for-gestational age; RPG, random plasma glucose; HbA1c, hemoglobin A1C; ODIP, overt diabetes in pregnancy; NGT, normal glucose tolerance.

Table 5 Use of FPG, HbA1c or pGCD59 as a Screening Tool

Author, Year/Country (Ref.)	Design	Subjects (N)	Study Population	Comparison	Main Results
FPG
Agarwal, 2010/UAE^Citation45	Retrospective cohort study	10,283	All pregnant women screened for GDM at 24–28 weeks	GDM diagnosis based on IADPSG vs ADA criteria /FPG ≥4.2 mmol/L vs ≥4.4 mmol/lL vs ≥4.7 mmol/L vs 5.0 mmol/L vs 5.1 mmol/L	Rule-in/rule-out approach for FPG to predict GDM with FPG ≥ 5.1 mmol/L ruling in GDM in 28.9% of women with 100% specificity and FPG < 4.4 mmol/L ruling out GDM in 21.7% women at a sensitivity of 95.4%, eliminating half of the OGTTs needed
Göbl, 2012/Austria^Citation93	Secondary analysis of a prospective cohort study	1336	Women without ODIP	Elaboration of a screening algorithm combining (1) FPG and (2) a multivariable risk estimation model focused on individuals with normal FPG levels to decide if a further OGTT is indicated	A risk estimation model in addition to FPG was accurate for detecting GDM in participants with normal FPG
Maesa, 2018/Spain^Citation92	Retrospective study	6573	All pregnant women	Three groups: normal glycaemia vs glucose intolerance (1 point in OGTT equal or above established thresholds) vs GDM diagnosis	Women with FPG ≤3.4 mmol/L were at low risk of developing GDM with a sensitivity of 91.3%, thereby avoiding a two-step screening in 10% of their population
Saeedi, 2018/Sweden^Citation91	Cross-sectional population-based study	3616	All pregnant women	Risk factors and FPG vs IADPSG criteria for GDM diagnosis	Risk factor screening for GDM was poorly predictive, but FPG of 4.8–5.0 mmol/L high sensitivity and specificity irrespective of diagnostic model and resulted in a low rate of OGTTs
Dickson, 2020/South Africa^Citation90	Cross-sectional prospective study	589	Pregnant women without ODIP <28 weeks	Selective screening (risk factor based) vs universal application of FPG ≥4.5 mmol/L to identify women with GDM	Universal screening using FPG ≥4.5 mmol/L had greater sensitivity and specificity in identifying GDM and required fewer women to undergo a resource-intensive diagnostic OGTT than selective screening
FPG
O’Connor, 2012/Ireland^Citation98	Prospective cohort study	311	Non-diabetic Caucasian pregnant and non-pregnant women	Non-pregnant vs T1 (trimester 1) vs T2 vs T3	HbA1c trimester-specific reference intervals are required to better inform the management of pregnancies complicated by diabetes
Lowe, 2012/International^Citation96	Secondary analysis of a prospective cohort study	21,064	Singleton pregnancies without ODIP	Association of HbA1c and model 1 vs model 2 vs model 3	Associations were significantly stronger with glucose measures than with HbA1C for adverse neonatal outcomes, suggesting that measurement of HbA1c is not a useful alternative to an OGTT for diagnosing GDM in pregnant women
Rajput, 2012/India^Citation49	Prospective cohort study	607	Women without ODIP	ADA vs IADPSG criteria/OGTT in combination with HbA1c <5.45% vs 5.45–5.95% vs >5.95%	HbA1c in combination with an OGTT obviated the need of OGTT in 61.8% of GDM cases and HbA1c >5.95% could be used to diagnose GDM in pregnant women with a specificity of 92.7%
Renz, 2015/Brazil^Citation97	Diagnostic test accuracy study	262	Pregnant women without ODIP	Reference test (OGTT) vs index test (HbA1c)/sensitivity, specificity and likelihood ratios of different HbA1c cut-off points	Different HbA1c cut-off points in combination with an OGTT may be a useful diagnostic tool for GDM
Khalafallah, 2016/Australia^Citation99	Prospective cohort study	480	Singleton pregnancies without early GDM diagnosis (<24 weeks)	HbA1c levels (4.6–10%) vs OGTT results	Pregnant women with an HbA1c of ≥5.4% should proceed with an OGTT, resulting in a significant reduction in the burden of testing
Odsaeter, 2016/Norway^Citation100	Retrospective analysis of RCT data	677	Singleton viable pregnancies without high risk	HbA1c levels alone or in combination with patient characteristics and GDM-WHO vs GDM-IADPSG	HbA1c may have a potential for screening for GDM since it is possible to exclude GDM in a significant proportion of women and could therefore reduce the number of OGTTs
pGCD59
Ghosh, 2017/US^Citation102	Case-control study	1000	Women undergoing routine two-step GDM screening	pGCD59 in women with normal GCT (control subjects) vs women with a failed GCT and a subsequent OGTT (case patients)	One pGCD59 measurement during weeks 24–28 identified pregnancy-induced glucose intolerance with high sensitivity and specificity and could potentially identify the risk for LGA
Ma, 2020/Europe^Citation103	Ancillary descriptive study	693	Obese women (BMI> 29) undergoing a 75g, 2h OGTT at <20 weeks	pGCD59 in NGT women vs GDM diagnosed <20 weeks vs GDM diagnosed 24–28 weeks	pGCD59 accurately identified GDM in early pregnancy; One-unit increase in maternal pGCD59 level was associated with 36% increased odds of delivering an LGA infant
Bogdanet, 2020 (ongoing)/Ireland^Citation104	Prospective cohort study	±2000	Pregnant women without ODIP	pGCD59 at first antenatal visit, 24–28 weeks, in T3 and at 12 weeks postpartum vs 75g OGTT/ sensitivity and specificity of pGCD59 to predict the results of the OGTT, adverse outcomes and/or postpartum glucose intolerance	No results published yet

Abbreviations: UAE, United Arab Emirates; GDM, gestational diabetes mellitus; IADPSG, International Association of the Diabetes and Pregnancy Study Groups; ODIP, overt diabetes in pregnancy; ADA, American Diabetes Association; FPG, fasting plasma glucose; OGTT, oral glucose tolerance test; GCT, glucose challenge test; NDDG, National Diabetes Data Group; WHO, World Health Organization; HbA1c, hemoglobin A1C; pGCD59, plasma glycatedCD59; LGA, large for gestational age; BMI, body mass index.

Table 6 Screening During the COVID-19 Pandemic

Author, Year/Country (Ref.)	Pragmatic Approach	Main Results
Torlone, 2020/Italy^Citation117	Screening for overt diabetes: FPG ≥6.9 mmol/L or RPG ≥11.1 mmol/L or HbA1c ≥6.5% A single value can be considered valid during COVID-19 emergency Screening for GDM: risk factors assessment Women at high risk for GDM: FPG ≥5.1 mmol/L at 16–18 weeks → GDM Women at high risk for GDM: FPG ≤5.1 mmol/L at 16–18 weeks → FPG at 24–28 weeks ≥5.1 mmol/L → GDM Women at medium risk for GDM: FPG ≥5.1 mmol/L at 24–28 weeks → GDM	An FPG value can be considered diagnostic for GDM only when it is obtained at the gestational age when the OGTT should have been carried out (16–18 weeks in high-risk pregnant women or 24–28 weeks in medium-risk women)
McIntyre, 2020 (Diagnosis and management of GDM during COVID-19)/UK, Canada and Australia^Citation112	Early in pregnancy: all guidelines: HbA1c ≥ 5.9% Standard screening (24–28 weeks): UK: at risk; GDM if HbA1c ≥ 5.7% and/or FPG ≥ 5.6 mmol/L and/or RPG (not preferred) ≥ 9.0 mmol/L CAN: GDM if HbA1c ≥ 5.7% and/or RPG ≥ 11.1 mmol/L AUS: FPG <4.7 mmol/L=normal; FPG 4.7–5.0 mmol/L=OGTT (WHO 2013 criteria); FPG ≥5.1 mmol/L=GDM	Detecting only those with marked hyperglycemia
Thangaratinam, 2020^Citation115	Early GDM screening: additional tests at booking (HbA1c and RPG) to detect overt diabetes and identify those at highest risk for GDM. Suggested thresholds and actions: HbA1c ≥ 6.5% or RPG ≥ 11.1 mmol/L: treat as preexisting diabetes. HbA1c 5.9–6.5% or RPG 9–11 mmol/L: consider managing using the GDM pathway. Avoid OGTT at 24–28 weeks and instead offer HbA1c along with FPG or RPG if fasting values are not available Suggested thresholds and actions: HbA1c ≥ 5.7% or FPG ≥ 5.6 mmol/L or RPG ≥ 9 mmol/L: treat as GDM.	Using FPG alone will only pick up half of all women with GDM, based on NICE or IADPSG criteria. Combining FPG with HbA1c may improve the detection rate. Maintaining existing FPG thresholds may be preferable, and services may consider lower thresholds consistent with the IADPSG diagnostic criteria (FPG ≥ 5.1) if resources allow
Van Gemert, 2020/Australia^Citation119	ADIPS temporary criteria during the COVID-19 pandemic are based on the Queensland Clinical Guidelines: HbA1c measurement in the first trimester for women with risk factors FPG at 24–28 weeks gestation for women not already diagnosed with GDM → GDM diagnosis if FPG is ≥5.1 mmol/L, no OGTT required if FPG ≤4.6 mmol/L, OGTT recommended if FPG of 4.7–5.0 mmol/L	Using a FPG ≤4.6 mmol/L as cut-off to determine that a 75g 2h OGTT is not necessary will reduce the number of women being potentially exposed, but would miss nearly a third of GDM cases
Meek, 2020/UK, Canada, New Zealand and Australia^Citation114	To evaluate the diagnostic and prognostic performance of alternative diagnostic strategies to 2h 75g OGTTs: HbA1c, RPG and FPG GDM diagnosis: criteria of the UK National Institute for Health and Care Excellence and IADPSG criteria	RPG at 12 weeks, and FPG or HbA1c at 28 weeks identify women with hyperglycemia at risk of suboptimal pregnancy outcomes
McIntyre, 2020 (Testing for GDM during COVID-19)/UK, Canada and Australia^Citation113	UK: Risk factor based; no OGTT; GDM if HbA1c ≥ 5.7% and/or FPG ≥ 5.6 mmol/L and/or RPG ≥ 9.0 mmol/L CAN: universal testing; no OGTT; GDM if HbA1c ≥ 5.7% and/or random VPG ≥ 11.1 mmol/L AUS: FPG < 4.7 mmol/L = normal; FPG 4.7–5.0 mmol/L = OGTT (WHO 2013 criteria); FPG ≥ 5.1 mmol/L = GDM	All post COVID-19 modified pathways reduced GDM frequency. Missed GDMs in Canada gave similar rates of pregnancy complications, while using UK and Australian modifications, the missed GDM group was at slightly and substantially lower risk.
Seshiah, 2020/India^Citation116	“Single test procedure” for diagnosing GDM: 2h PG ≥ 7.8 mmol/L with 75g oral glucose administered to a pregnant woman in the fasting or non-fasting state, without regard to the time of the last meal (glucose load can also be taken at home and the pregnant woman can visit the hospital 2h after the glucose ingestion to give a single sample for plasma glucose estimation)	The economical and evidence based “single test procedure” of DIPSI is most appropriate for screening during COVID-19 as performing OGTTs is resource intensive, the fasting state is impractical with very high dropout rate.
Van-de-l’Isle, 2020/UK^Citation121	NICE guidelines methodology (75g 2h OGTT) vs RCOG COVID testing for GDM (two-step testing approach): First, women with risk factors for GDM (according to NICE) are tested with HbA1c and RPG at booking → RPG ≥11.1 mmol/L is diagnostic of T2DM, and HbA1c value of 6.8–7.7% is considered indicative of pre-diabetes (women with a value in this range and a prior history of GDM are managed as GDM) Testing at 28 weeks is recommended and a diagnosis of GDM is made if any of the following criteria were satisfied: FPG ≥5.3 mmol/L or HbA1c ≥ 5.7% or RPG ≥9 mmol/L	The overall rate of women identified as having GDM decreased from 7.7% to 4.2% and the COVID-19 regimen failed to detect 57% women identified as GDM
Nachtergaele, 2021/France^Citation118	Reference standard testing: OGTT at 22–30 weeks according to IADPSG/WHO criteria applying universal screening Seven tested algorithms (termed as “Options”): OGTT only in women with risk factor for HIP, ie, applying selective screening (Option Sel); OGTT in women with FPG 4.7–5.0 mmol/L at 22–30 weeks, applying universal (Option 1) or selective screening (Option 1-Sel) OGTT in women without history of HIP (previous HIP is considered as GDM) and with FPG 4.7–5.0 mmol/L at 22–30 weeks, applying universal (Option 2) or selective screening (Option 2-Sel) FPG alone measured, applying universal (Option 3) or selective screening (Option 3-Sel)	Consideration of a history of HIP and measuring first FPG can avoid more than 80% of OGTTs and identify women with the highest risk of adverse HIP-related events
Zhu, 2021 /Australia^Citation120	Initial division into groups according to FPG results (mmol/L): FPG <4.7, FPG 4.7–5.0 and FPG ≥5.1 Division into groups according to how GDM was managed during pregnancy: diet, metformin (MF), insulin and MF + insulin	HbA1c and FPG are poor screening tests for GDM. During the COVID-19 pandemic, the OGTT should be given clinical priority in high-risk patients, an HbA1c cut-off of 5.7% is proposed if it is used for screening. Elevated FPG is a significant predictor for needing medical management for GDM and could be used to enable individualized treatment

Abbreviations: FPG, fasting plasma glucose; RPG, random plasma glucose; HbA1c, hemoglobin A1c; GDM, gestational diabetes mellitus; OGTT, oral glucose tolerance test; UK, United Kingdom; CAN, Canada; AUS, Australia; WHO, World Health Organization; NICE, National Institute for Health and Care Excellence; IADPSG, International Association of the Diabetes and Pregnancy Study Groups; ADIPS, Australasian diabetes in pregnancy society; RCOG, Royal College of Obstetricians and Gynaecologists; T2DM, type 2 diabetes mellitus; HIP, hyperglycemia in pregnancy; MF, metformin.

Bartha JL , Martinez-Del-Fresno P , Comino-Delgado R . Early diagnosis of gestational diabetes mellitus and prevention of diabetes-related complications. Eur J Obstet Gynecol Reprod Biol . 2002;109(1):41–44. doi:10.1016/S0301-2115(02)00480-3

 Web of Science ®Google Scholar

Riskin-Mashiah S , Younes G , Damti A , Auslender R . First-trimester fasting hyperglycemia and adverse pregnancy outcomes. Diabetes Care . 2009;32(9):1639–1643. doi:10.2337/dc09-0688 19549728

 PubMed Web of Science ®Google Scholar

van Leeuwen M , Opmeer B , Zweers E , et al. Estimating the risk of gestational diabetes mellitus: a clinical prediction model based on patient characteristics and medical history. BJOG an Int J Obstet Gynaecol . 2010;117(1):69–75. doi:10.1111/j.1471-0528.2009.02425.x

 Web of Science ®Google Scholar

Teede HJ , Harrison CL , Teh WT , Paul E , Allan CA . Gestational diabetes: development of an early risk prediction tool to facilitate opportunities for prevention. Aust N Z J Obstet Gynaecol . 2011;51(6):499–504. doi:10.1111/j.1479-828X.2011.01356.x 21951203

 PubMed Web of Science ®Google Scholar

Zhu WW , Yang HX , Wei YM , et al. Evaluation of the value of fasting plasma glucose in the first prenatal visit to diagnose gestational diabetes mellitus in china. Diabetes Care . 2013;36(3):586–590. doi:10.2337/dc12-1157 23193214

 PubMed Web of Science ®Google Scholar

Alunni ML , Roeder HA , Moore TR , Ramos GA . First trimester gestational diabetes screening - change in incidence and pharmacotherapy need. Diabetes Res Clin Pract . 2015;109(1):135–140. doi:10.1016/j.diabres.2015.04.027 25958098

 PubMed Web of Science ®Google Scholar

Hong WY , Biggio JR , Tita A , Harper LM . Impact of early screening for gestational diabetes on perinatal outcomes in high-risk women. Am J Perinatol . 2016;33(8):758–764. doi:10.1055/s-0036-1571317 26890436

 PubMed Web of Science ®Google Scholar

Sweeting AN , Ross GP , Hyett J , et al. Baseline HbA1c to identify high-risk gestational diabetes: utility in early vs standard gestational diabetes. J Clin Endocrinol Metab . 2017;102(1):150–156. doi:10.1210/jc.2016-2951 27797673

 PubMed Web of Science ®Google Scholar

Mañe L , Flores-le Roux JA , Benaiges D , et al. Role of first-trimester HbA1c as a predictor of adverse obstetric outcomes in a multiethnic cohort. J Clin Endocrinol Metab . 2017;102(2):390–397. doi:10.1210/jc.2016-2581 27880069

 PubMed Web of Science ®Google Scholar

Benaiges D , Flores-le Roux JA , Marcelo I , et al. Is first-trimester HbA1c useful in the diagnosis of gestational diabetes? Diabetes Res Clin Pract . 2017;133:85–91. doi:10.1016/j.diabres.2017.08.019 28918341

 PubMed Web of Science ®Google Scholar

Hosseini E , Janghorbani M , Shahshahan Z . Comparison of risk factors and pregnancy outcomes of gestational diabetes mellitus diagnosed during early and late pregnancy. Midwifery . 2018;66:64–69. doi:10.1016/j.midw.2018.07.017 30130677

 PubMed Web of Science ®Google Scholar

Ryan DK , Haddow L , Ramaesh A , et al. Early screening and treatment of gestational diabetes in high-risk women improves maternal and neonatal outcomes: a retrospective clinical audit. Diabetes Res Clin Pract . 2018;144:294–301. doi:10.1016/j.diabres.2018.09.013 30244050

 PubMed Web of Science ®Google Scholar

Bianchi C , de Gennaro G , Romano M , et al. Early vs. standard screening and treatment of gestational diabetes in high-risk women - an attempt to determine relative advantages and disadvantages. Nutr Metab Cardiovasc Dis . 2019;29(6):598–603. doi:10.1016/j.numecd.2019.02.007 30954416

 PubMed Web of Science ®Google Scholar

Boe B , Barbour LA , Allshouse AA , Heyborne KD . Universal early pregnancy glycosylated hemoglobin A1c as an adjunct to Carpenter-Coustan screening: an Observational Cohort Study. Am J Obstet Gynecol . 2019;1(1):24–32.

 Web of Science ®Google Scholar

Punnose J , Malhotra RK , Sukhija K , Mathew A , Sharma A , Choudhary N . Glycated haemoglobin in the first trimester: a predictor of gestational diabetes mellitus in pregnant Asian Indian women. Diabetes Res Clin Pract . 2020;159:107953. doi:10.1016/j.diabres.2019.107953 31794807

 PubMed Web of Science ®Google Scholar

Benhalima K , Van Crombrugge P , Moyson C , et al. Estimating the risk of gestational diabetes mellitus based on the 2013 WHO criteria: a prediction model based on clinical and biochemical variables in early pregnancy. Acta Diabetol . 2020;57(6):661–671. doi:10.1007/s00592-019-01469-5 31915927

 PubMed Web of Science ®Google Scholar

Cosson E , Vicaut E , Berkane N , et al. Prognosis associated with initial care of increased fasting glucose in early pregnancy: a retrospective study. Diabetes Metab . 2020.

 Web of Science ®Google Scholar

Liu B , Cai J , Xu Y , et al. Early diagnosed gestational diabetes mellitus is associated with adverse pregnancy outcomes: a prospective cohort study. J Clin Endocrinol Metab . 2020;105(12):e4264–e4274. doi:10.1210/clinem/dgaa633

 Web of Science ®Google Scholar

Benhalima K , Van Crombrugge P , Moyson C , et al. Women with mild fasting hyperglycemia in early pregnancy have more neonatal intensive care admissions. J Clin Endocrinol Metab . 2021;106(2):e836–e854. doi:10.1210/clinem/dgaa831 33180931

 PubMed Web of Science ®Google Scholar

Osmundson SS , Norton ME , El-Sayed YY , Carter S , Faig JC , Kitzmiller JL . Early screening and treatment of women with prediabetes: a randomized controlled trial. Am J Perinatol . 2016;33(2):172–179. doi:10.1055/s-0035-1563715 26344009

 PubMed Web of Science ®Google Scholar

Hughes RCE , Rowan J , Williman J , Ruth D , Hughes CE . Prediabetes in pregnancy, can early intervention improve outcomes? A feasibility study for a parallel randomised clinical trial. BMJ Open . 2018;8(3):18493. doi:10.1136/bmjopen-2017-018493

 PubMed Web of Science ®Google Scholar

Simmons D , Hague WM , Teede HJ , et al. Hyperglycaemia in early pregnancy: the treatment of booking gestational diabetes mellitus (TOBOGM) Study. A randomised controlled trial. Med J Aust . 2018;209(9):405–406. doi:10.5694/mja17.01129 29793404

 PubMed Web of Science ®Google Scholar

Simmons D , Nema J , Parton C , et al. The treatment of booking gestational diabetes mellitus (TOBOGM) pilot randomised controlled trial. BMC Pregnancy Childbirth . 2018;18(1):151. doi:10.1186/s12884-018-1809-y 29747594

 PubMed Web of Science ®Google Scholar

Vinter CA , Tanvig MH , Christensen MH , et al. Lifestyle intervention in Danish obese pregnant women with early gestational diabetes mellitus according to WHO 2013 criteria does not change pregnancy outcomes: results from the LiP (Lifestyle in Pregnancy) Study. Diabetes Care . 2018;41(10):2079–2085. doi:10.2337/dc18-0808 30061318

 PubMed Web of Science ®Google Scholar

Roeder HA , Moore TR , Wolfson MT , Gamst AC , Ramos GA . Treating hyperglycemia in early pregnancy: a randomized controlled trial. Am J Obstet Gynecol . 2019;1(1):33–41.

 Web of Science ®Google Scholar

Harper LM , Jauk V , Longo S , Biggio JR , Szychowski JM , Tita AT . Early gestational diabetes screening in obese women: a randomized controlled trial. Am J Obstet Gynecol . 2020;222(5):495.e1–495.e8. doi:10.1016/j.ajog.2019.12.021

 Web of Science ®Google Scholar

The effect of early screening and intervention for gestational diabetes mellitus on pregnancy outcomes. Available from: https://clinicaltrials.gov/ct2/show/NCT03523143. Accessed 3 30, 2021.

 Google Scholar

Agarwal MM , Dhatt GS , Shah SM . Gestational diabetes mellitus: simplifying the international association of diabetes and pregnancy diagnostic algorithm using fasting plasma glucose. Diabetes Care . 2010;33(9):2018–2020. doi:10.2337/dc10-0572 20519664

 PubMed Web of Science ®Google Scholar

Rajput R , Yadav Y, Rajput M , Nanda S . Utility of HbA 1c for diagnosis of gestational diabetes mellitus. Diabetes Res Clin Pract . 2012;98(1):104–107. doi:10.1016/j.diabres.2012.02.018 22456454

 PubMed Web of Science ®Google Scholar

Benhalima K , Hanssens M , Devlieger R , Verhaeghe J , Mathieu C . Analysis of pregnancy outcomes using the new IADPSG recommendation compared with the Carpenter and Coustan criteria in an area with a low prevalence of gestational diabetes. Int J Endocrinol . 2013;2013:1–6. doi:10.1155/2013/248121

 Web of Science ®Google Scholar

Duran A , Śaenz S , Torrejon MJ , et al. Introduction of IADPSG criteria for the screening and diagnosis of gestational diabetes mellitus results in improved pregnancy outcomes at a lower cost in a large cohort of pregnant women: the St. Carlos Gestational Diabetes Study. Diabetes Care . 2014;37(9):2442–2450. doi:10.2337/dc14-0179 24947793

 PubMed Web of Science ®Google Scholar

Fuller KP , Borgida AF . Gestational diabetes mellitus screening using the one-step versus two-step method in a high-risk practice. Clin Diabetes . 2014;32(4):148–150. doi:10.2337/diaclin.32.4.148 25646939

 PubMedGoogle Scholar

Hung TH , Hsieh TT . The effects of implementing the international association of diabetes and pregnancy study groups criteria for diagnosing gestational diabetes on maternal and neonatal outcomes. PLoS One . 2015;10(3):e0122261. doi:10.1371/journal.pone.0122261 25756838

 PubMed Web of Science ®Google Scholar

Meek CL , Lewis HB , Patient C , Murphy HR , Simmons D . Diagnosis of gestational diabetes mellitus: falling through the net. Diabetologia . 2015;58(9):2003–2012. doi:10.1007/s00125-015-3647-z 26071759

 PubMed Web of Science ®Google Scholar

Feldman RK , Tieu RS , Yasumura L . Gestational diabetes screening: the international association of the diabetes and pregnancy study groups compared with Carpenter-Coustan screening. Obstet Gynaecol . 2016;127(1):10–17. doi:10.1097/AOG.0000000000001132

 PubMed Web of Science ®Google Scholar

March MI , Modest AM , Ralston SJ , Hacker MR , Gupta M , Brown FM . The effect of adopting the IADPSG screening guidelines on the risk profile and outcomes of the gestational diabetes population. J Matern Fetal Neonatal Med . 2016;29(7):1141–1145. doi:10.3109/14767058.2015.1038513 25958989

 PubMed Web of Science ®Google Scholar

Waters TP , Dyer AR , Scholtens DM , et al. Maternal and neonatal morbidity for women who would be added to the diagnosis of GDM using IADPSG criteria: a secondary analysis of the hyperglycemia and adverse pregnancy outcome study. Diabetes Care . 2016;39(12):2204–2210. doi:10.2337/dc16-1194 27634392

 PubMed Web of Science ®Google Scholar

Huhn EA , Massaro N , Streckeisen S , et al. Fourfold increase in prevalence of gestational diabetes mellitus after adoption of the new international association of diabetes and pregnancy study groups (IADPSG) criteria. J Perinat Med . 2017;45(3):359–366. doi:10.1515/jpm-2016-0099 27508951

 PubMed Web of Science ®Google Scholar

Adam S , Rheeder P . Screening for gestational diabetes mellitus in a South African population: prevalence, comparison of diagnostic criteria and the role of risk factors. S Afr Med J . 2017;107(6):523–527. doi:10.7196/SAMJ.2017.v107i6.12043 28604326

 PubMed Web of Science ®Google Scholar

Luewan S , Bootchaingam P , Tongsong T . Comparison of the screening tests for gestational diabetes mellitus between “one-step” and “two-step” methods among Thai pregnant women. Obstet Gynaecol Int . 2018;2018:1521794.

 PubMed Web of Science ®Google Scholar

Goedegebure EAR , Koning SH , Hoogenberg K , et al. Pregnancy outcomes in women with gestational diabetes mellitus diagnosed according to the WHO-2013 and WHO-1999 diagnostic criteria: a multicentre retrospective cohort study. BMC Pregnancy Childbirth . 2018;18(1). doi:10.1186/s12884-018-1810-5

 Web of Science ®Google Scholar

Benhalima K , Van Crombrugge P , Moyson C , et al. The sensitivity and specificity of the glucose challenge test in a universal two-step screening strategy for gestational diabetes mellitus using the 2013 World Health Organization criteria. Diabetes Care . 2018;41(7):e111–e112. doi:10.2337/dc18-0556 29748432

 PubMed Web of Science ®Google Scholar

Pocobelli G , Yu O , Fuller S , et al. One-step approach to identifying gestational diabetes mellitus: association with perinatal outcomes. Obstet Gynaecol . 2018;132(4):859–867. doi:10.1097/AOG.0000000000002780

 Web of Science ®Google Scholar

Costa E , Kirckpartick C , Gerday C , et al. Change in prevalence of gestational diabetes and obstetric complications when applying IADPSG screening criteria in a Belgian French speaking University Hospital. A Retrospective Cohort Study. BMC Pregnancy Childbirth . 2019;19(1):249. doi:10.1186/s12884-019-2406-4 31311547

 PubMed Web of Science ®Google Scholar

Cade TJ , Polyakov A , Brennecke SP . Implications of the introduction of new criteria for the diagnosis of gestational diabetes: a health outcome and cost of care analysis. BMJ Open . 2019;9(1):e023293. doi:10.1136/bmjopen-2018-023293

 PubMed Web of Science ®Google Scholar

Meloncelli NJL , Barnett AG , D’Emden M , De Jersey SJ . Effects of changing diagnostic criteria for gestational diabetes mellitus in Queensland, Australia. Obstet Gynaecol . 2020;135(5):1215–1221. doi:10.1097/AOG.0000000000003790

 Web of Science ®Google Scholar

Mirzamoradi M , Bakhtiyari M , Kimiaee P , Hosseini-Najarkolaei A , Mansournia MA . Investigating the effects of treatment based on single high blood glucose in gestational diabetes screening on maternal and neonatal complications. Arch Gynecol Obstet . 2015;292(3):687–695. doi:10.1007/s00404-015-3670-9 25753159

 PubMed Web of Science ®Google Scholar

Abebe KZ , Scifres C , Simhan HN , et al. Comparison of two screening strategies for gestational diabetes (GDM(2)) trial: design and rationale. Contemp Clin Trials . 2017;62:43–49. doi:10.1016/j.cct.2017.08.012 28823926

 PubMed Web of Science ®Google Scholar

Satodiya M , Takkar N , Goel P , Kaur J . Comparison of one-step versus two-step screening for diagnosis of GDM in Indian population: a randomized controlled trial. J Obstet Gynaecol India . 2017;67(3):190–195. doi:10.1007/s13224-016-0955-2 28546666

 PubMed Web of Science ®Google Scholar

Fadl H , Saeedi M , Montgomery S , et al. Changing diagnostic criteria for gestational diabetes in Sweden - a stepped wedge national cluster randomised controlled trial - The CDC4G Study protocol. BMC Pregnancy Childbirth . 2019;19(1). doi:10.1186/s12884-019-2547-5

 Web of Science ®Google Scholar

Hillier TA , Pedula KL , Ogasawara KK , et al. A pragmatic, randomized clinical trial of gestational diabetes screening. N Engl J Med . 2021;384(10):895–904. doi:10.1056/NEJMoa2026028 33704936

 PubMed Web of Science ®Google Scholar

Cosson E , Benchimol M , Carbillon L , et al. Universal rather than selective screening for gestational diabetes mellitus may improve fetal outcomes. Diabetes Metab . 2006;32(2):140–146. doi:10.1016/S1262-3636(07)70260-4 16735962

 PubMed Web of Science ®Google Scholar

Dahanayaka NJ , Agampodi SB , Ranasinghe OR , et al. Inadequacy of the risk factor based approach to detect gestational diabetes mellitus. Ceylon Med J . 2012;57(1):5–9. doi:10.4038/cmj.v57i1.4193 22453704

 PubMedGoogle Scholar

Arora D , Arora R , Sangthong S , Leelaporn W , Sangratanathongchai J . Universal screening of gestational diabetes mellitus: prevalence and diagnostic value of clinical risk factors. J Med Assoc Thai . 2013;96(3):266–271.23539927

 PubMedGoogle Scholar

Avalos GE , Owens LA , Dunne F . Applying current screening tools for gestational diabetes mellitus to a European population: is it time for change? Diabetes Care . 2013;36(10):3040–3044. doi:10.2337/dc12-2669 23757431

 PubMed Web of Science ®Google Scholar

Olagbuji BN , Atiba AS , Olofinbiyi BA , et al. Prevalence of and risk factors for gestational diabetes using 1999, 2013 WHO and IADPSG criteria upon implementation of a universal one-step screening and diagnostic strategy in a Sub-Saharan African population. Eur J Obstet Gynecol Reprod Biol . 2015;189:27–32. doi:10.1016/j.ejogrb.2015.02.030 25855324

 PubMed Web of Science ®Google Scholar

Miailhe G , Kayem G , Girard G , Legardeur H. M , Elbrot L . Selective rather than universal screening for gestational diabetes mellitus? Eur J Obstet Gynecol Reprod Biol . 2015;191:95–100. doi:10.1016/j.ejogrb.2015.05.003 26112365

 PubMed Web of Science ®Google Scholar

Herath HM , Weerarathna TP , Weerasinghe NP . Is risk factor-based screening good enough to detect gestational diabetes mellitus in high-risk pregnant women? A Sri Lankan experience. Int J Prev Med . 2016;7(99).

 Google Scholar

Agbozo F , Abubakari A , Narh C , Jahn A . Accuracy of glycosuria, random blood glucose and risk factors as selective screening tools for gestational diabetes mellitus in comparison with universal diagnosing. BMJ Open Diabetes Res Care . 2018;6(1):e000493. doi:10.1136/bmjdrc-2017-000493

 Web of Science ®Google Scholar

Benhalima K , Van Crombrugge P , Moyson C , et al. Risk factor screening for gestational diabetes mellitus based on the 2013 WHO criteria. Eur J Endocrinol . 2019;180(6):353–363. doi:10.1530/EJE-19-0117 31120231

 PubMed Web of Science ®Google Scholar

Matta-Coelho C , Monteiro AM , Fern EV , Pereira ML , Souto SB . Universal vs. risk-factor-based screening for gestational diabetes-an analysis from a 5-year Portuguese cohort. Endocrine . 2019;63(3):507–512. doi:10.1007/s12020-018-1760-8 30255292

 PubMed Web of Science ®Google Scholar

Göbl CS , Bozkurt L , Rivic P , et al. A two-step screening algorithm including fasting plasma glucose measurement and a risk estimation model is an accurate strategy for detecting gestational diabetes mellitus. Diabetologia . 2012;55(12):3173–3181. doi:10.1007/s00125-012-2726-7 23001377

 PubMed Web of Science ®Google Scholar

Maesa JM , Fern E-RP , Sanchez-Margalet V , Gonzalez-Rodriguez C . Fasting glycemia as screening tool to rule-out gestational diabetes in low-risk population. Clin Lab . 2018;64(4):461–465. doi:10.7754/Clin.Lab.2017.170920 29739067

 PubMed Web of Science ®Google Scholar

Saeedi M , Hanson U , Simmons D , Fadl H . Characteristics of different risk factors and fasting plasma glucose for identifying GDM when using IADPSG criteria: a cross-sectional study. BMC Pregnancy Childbirth . 2018;18(1):225. doi:10.1186/s12884-018-1875-1 29898685

 PubMed Web of Science ®Google Scholar

Dickson LM , Buchmann EJ , van Rensburg C , Norris SA . Fasting plasma glucose and risk factor assessment: comparing sensitivity and specificity in identifying gestational diabetes in urban black African women. S Afr Med J . 2020;110(1):21–26. doi:10.7196/SAMJ.2019.v110i1.14089

 Web of Science ®Google Scholar

O’Connor C , O’Shea PM , Owens LA , et al. Trimester-specific reference intervals for haemoglobin A1c (HbA1c) in pregnancy. Clin Chem Lab Med . 2012;50(5):905–909. doi:10.1515/cclm.2011.397

 Web of Science ®Google Scholar

Lowe LP , Coustan DR , Metzger BE , et al. Hyperglycemia and adverse pregnancy outcome (HAPO) Study: associations of maternal A1C and glucose with pregnancy outcomes. Diabetes Care . 2012;35(3):574–580. doi:10.2337/dc11-1687 22301123

 PubMed Web of Science ®Google Scholar

Renz PB , Cavagnolli G , Weinert LS , Silveiro SP , Camargo JL . HbA1c test as a tool in the diagnosis of gestational diabetes mellitus. PLoS One . 2015;10(8):e0135989. doi:10.1371/journal.pone.0135989 26292213

 PubMed Web of Science ®Google Scholar

Khalafallah A , Phuah E , Al-Barazan AM , et al. Glycosylated haemoglobin for screening and diagnosis of gestational diabetes mellitus. BMJ Open . 2016;6(4):e011059. doi:10.1136/bmjopen-2016-011059

 PubMed Web of Science ®Google Scholar

Odsaeter IH , Åsberg A , Vanky E , et al. Hemoglobin A1c as screening for gestational diabetes mellitus in Nordic Caucasian women. Diabetol Metab Syndr . 2016;8(1):43. doi:10.1186/s13098-016-0168-y 27453735

 PubMed Web of Science ®Google Scholar

Ghosh P , Luque-Fernandez MA , Vaidya A , et al. Plasma glycated CD59, a novel biomarker for detection of pregnancy-induced glucose intolerance. Diabetes Care . 2017;40(7):981–984. doi:10.2337/dc16-2598 28450368

 PubMed Web of Science ®Google Scholar

Ma DD , Luque-Fernandez MA , Bogdanet D , Desoye G , Dunne F , Halperin JA . Plasma glycated CD59 predicts early gestational diabetes and large for gestational age newborns. J Clin Endocrinol Metab . 2020;105(4):E1033–E1040. doi:10.1210/clinem/dgaa087

 Web of Science ®Google Scholar

Bogdanet D , O’Shea PM , Halperin J , Dunne F . Plasma glycated CD59 (gCD59), a novel biomarker for the diagnosis, management and follow up of women with Gestational Diabetes (GDM) - protocol for prospective cohort study. BMC Pregnancy Childbirth . 2020;20(1):412. doi:10.1186/s12884-020-03090-9 32682411

 PubMed Web of Science ®Google Scholar

Torlone E , Festa C , Formoso G , et al. Italian recommendations for the diagnosis of gestational diabetes during COVID-19 pandemic: position statement of the Italian Association of Clinical Diabetologists (AMD) and the Italian Diabetes Society (SID), diabetes, and pregnancy study group. Nutr Metab Cardiovasc Dis . 2020;30(9):1418–1422. doi:10.1016/j.numecd.2020.05.023 32675009

 PubMed Web of Science ®Google Scholar

McIntyre HD , Moses RG . The diagnosis and management of gestational diabetes mellitus in the context of the COVID-19 pandemic. Diabetes Care . 2020;43(7):1433–1434. doi:10.2337/dci20-0026 32409503

 PubMed Web of Science ®Google Scholar

Thangaratinam S , Cooray SD , Sukumar N , et al. Endocrinology in the time of COVID-19: diagnosis and management of gestational diabetes mellitus. Eur J Endocrinol . 2020;183(2):G49–g56. doi:10.1530/EJE-20-0401 32454456

 PubMed Web of Science ®Google Scholar

van Gemert TE , Moses RG , Pape AV , Morris GJ . Gestational diabetes mellitus testing in the COVID-19 pandemic: the problems with simplifying the diagnostic process. Aust N Z J Obstet Gynaecol . 2020;60(5):671–674. doi:10.1111/ajo.13203 32662072

 PubMed Web of Science ®Google Scholar

Meek CL , Lindsay RS , Scott EM , et al. Approaches to screening for hyperglycaemia in pregnant women during and after the COVID-19 pandemic. Diabet Med . 2020;38(1):e14380. doi:10.1111/dme.14380 32750184

 PubMed Web of Science ®Google Scholar

McIntyre HD , Gibbons KS , Ma RCW , et al. Testing for gestational diabetes during the COVID-19 pandemic. An evaluation of proposed protocols for the United Kingdom, Canada and Australia. Diabetes Res Clin Pract . 2020;167:108353. doi:10.1016/j.diabres.2020.108353 32739381

 PubMed Web of Science ®Google Scholar

Seshiah V , Balaji V , Banerjee S . et al. Diagnosis and principles of management of gestational diabetes mellitus in the prevailing COVID-19 pandemic. Int J Diabetes Dev Ctries ;2020. 1–6. doi:10.1007/s13410-020-00860-1

 Web of Science ®Google Scholar

Van-de-l’isle Y , Steer PJ , Watt Coote I , Cauldwell M . Impact of changes to national UK guidance on testing for gestational diabetes screening during a pandemic: a single-centre observational study. BJOG . 2020;128(5):917–920. doi:10.1111/1471-0528.16482 32888369

 PubMed Web of Science ®Google Scholar

Nachtergaele C , Vicaut E , Tatulashvili S , et al. Limiting the use of oral glucose tolerance tests to screen for hyperglycemia in pregnancy during pandemics. J Clin Med . 2021;10(3):397. doi:10.3390/jcm10030397 33494289

 PubMed Web of Science ®Google Scholar

Zhu S , Meehan T , Veerasingham M , Sivanesan K . COVID-19 pandemic gestational diabetes screening guidelines: a retrospective study in Australian women. Diabetes Metab Syndr . 2021;15(1):391–395. doi:10.1016/j.dsx.2021.01.021 33571889

 PubMed Web of Science ®Google Scholar