Estimated fetal weight standards of the INTERGROWTH-21^st project for the prediction of adverse outcomes: a systematic review with meta-analysis

Figures & data

Table 1. Summary of studies characteristics.

Study	Country	Sample size	Study design	Predictors and cutoff points	EFW by:	Time-points of predictor measurement	% <p10	Results presented as:
Blue 2018 [6]	USA	831	retrospective cohort	EFW (<p5, <p10 and < p22)	IG-21^b	median: 6.5 days before delivery (range: 0–13 days)	14.6	Sens, Spec, AUC, PPV, NPV
Nwabuobi 2018 [7]	USA	1054	prospective cohort	Fetal growth restriction (EFW < p10)	Unclear	mean: 6.7 weeks before delivery	4.1	RR, Sens, Spec, AUC, PPV, NPV
Hua 2018 [5]	USA	9409	retrospective review of a clinical trial	SGA (EFW < p5 and < p10)	IG-21^b	18 - 24 weeks and 28 - 34 weeks	9.1	RR^e, Sens, Spec, AUC
Zhu 2019 [31]	China	690	prospective cohort	EFW < p5	IG-21^b	At 3rd trimester	NA	HR, Sens, Spec, AUC, PPV, NPV
Kabiri 2019 [8]	USA	3437	retrospective cohort	SGA (EFW < p10), LGA (EFW > p90)	IG-21^b	mean: 3.6 weeks before delivery;	13.2	RR, Sens, Spec, AUC, PPV, NPV, Partial AUC (FPR < 10%)
Nahirney 2019 [24]	USA	3782660	Cross-sectional	SGA (BW < p10), LGA (BW > p90)^a	BW	At birth	4.0	OR, AUC
Morales-Roselló 2019 [25]	Spain	714	prospective cohort	EFW (FPR 10% and 5%)	IG-21^b	mean: 8.03 days before delivery.	NA	AUC, beta (regression)
Savirón-Cornudella 2020 [35]	Spain	9585	retrospective cohort	EFW (cutoff unclear)	IG-21^b	34 to 36 gestational weeks	12.7	OR, AUC, Sens for fixed FPR
Vikraman and Elayedatt 2020 [32]	India	1019	prospective cohort	SGA (EFW < p5 and < p10)	Hadlock III^c	89.6% was measured between 32 and 36 weeks	6.5	Sens, Spec, PPV, NPV, FPR
Lorusso 2020 [17]	Brazil	194	retrospective cohort	LGA (EFW > p90)	Hadlock I§	Mean: 32 days before delivery	NA	Sens, Spec, PPV, NPV, Accuracy, FPR, FNR, LR+, LR-
Choi 2020 [33]	Australia	2217683	cross-sectional	SGA (BW < p3, <p5, <p10, <p25), LGA (BW > p90, >p95 and > p97)	BW	At birth	3.2	RR, Sens, Spec, AUC, PPV, NPV
Hiersch 2020 [28]	Canada	49458	retrospective cohort	SGA (BW < p10, <p25)	BW	At birth	3.4	Sens, PPV, NPV, LR+, LR-, FPR
Savirón-Cornudella 2021 [27]	Spain	9585	retrospective cohort	EFW (>p91.5, >p85.9, >p80.1, >p75.3)	IG-21^b	34 to 36 gestational weeks	7.9	OR, Sens, AUC
Kato 2020 [30]	Brazil	231	retrospective cohort	EFW < p10	Hadlock I^d	mean: 24 days before delivery	8.2	Sens, Spec, AUC, PPV, NPV
Sovio 2021 [34]	UK	3161	prospective cohort	EFW (90% Spec)	IG-21^b	28 weeks and 36 weeks	NA	Sens, AUC, +LR, -LR
Melamed 2021 [29]	Canada	742	prospective cohort	SGA (BW < p10, <p3)	BW	At birth	5.1	Sens, RR, FPR, Youden’s index

AUC: Area under the curve; BW: Birth weight; EFW: Estimated fetal weight; FPR: false positive rate; HR: Hazard ratio; LGA: Large for gestational age; NA: not available; OR: Odds ratio; RR: Risk ratios; p10: 10th percentile; Sens: sensitivity; SGA: Small for gestational age; Spec: specificity; USA: United States of America; UK: United Kingdom; % <p10: proportion of fetuses classified below the 10th percentile using IG-21 standard.

^a Used the IG-21 EFW chart to define percentiles of BW measures.

^blog(EFW) = 5.08482 - 54.06633 x (AC/100)³ - 95.80076 x (AC/100)³ x log(AC/100) + 3.136370 x (HC/100);.

^c log(EFW) = 1.326 – 0.00326 x AC x FL+ 0.0107 x HC + 0.0438 x AC + 0.158 x FL;.

^d log(EFW) = 1.3596 – 0.00386 x AC x FL + 0.0064 x HC + 0.00061 x BPD x AC + 0.0424 x AC +0.174 x FL;.

^e In methods described Relative Risk, but in figures presented Odds Ratio.

Figure 1. Quality assessment evaluation. (A) Risk of bias according to selected domains for each study; (B) Proportion of studies with low, high, and unclear risk of bias for each selected domain.

Figure 2. Estimate effects and pooled results for outcomes evaluated by two or more studies with similar cutoffs. It included only studies whose fetal weight was estimated by formulas based on USG measurements over 32 weeks of pregnancy. tp, true positives; fp, false positives; fn, false negatives; tn, true negatives; RR, relative risk; SGA, small for gestational age; NICU: neonatal intensive care unit; LGA: large for gestational age; For studies with a zero cell in the contingency table, the Stata command [metan] automatically adds 0.5 in all cells.

Figure 3. SROC curve for outcomes evaluated by two or more studies with similar cutoffs. It included only studies whose fetal weight was estimated by formulas based on USG measurements over 32 weeks of pregnancy. SGA: small for gestational age; NICU: neonatal intensive care unit; LGA: large for gestational age.

Blue NR, Savabi M, Beddow ME, et al. The hadlock method is superior to newer methods for the prediction of the birth weight percentile. J Ultrasound Med. 2019;38(3):587–596. DOI:10.1002/jum.14725.

 PubMed Web of Science ®Google Scholar

Nwabuobi C, Camisasca-Lopina H, Leavitt K, et al. INTERGROWTH-21st and hadlock growth standards to predict neonatal small for gestational age and short-term neonatal outcomes. Am J Obstet Gynecol. 2018;218(1):S310. DOI:10.1016/j.ajog.2017.11.044.

 Web of Science ®Google Scholar

Hua X, Shen M, Reddy UM, et al. Comparison of the INTERGROWTH‐21st, national institute of child health and human development, and WHO fetal growth standards. Int J Gynaecol Obstet. 2018;143(2):156–163. DOI:10.1002/ijgo.12637.

 PubMed Web of Science ®Google Scholar

Zhu C, Ren Y-Y, Wu J-N, et al. A comparison of prediction of adverse perinatal outcomes between hadlock and INTERGROWTH-21st standards at the third trimester. Biomed Res Int. 2019;2019:7698038. DOI:10.1155/2019/7698038.

 PubMed Web of Science ®Google Scholar

Kabiri D, Romero R, Gudicha DW, et al. Prediction of adverse perinatal outcomes by fetal biometry: a comparison of customized and population-based standards. Ultrasound Obstet Gynecol. 2020;55(2):177–188. DOI:10.1002/uog.20299.

 PubMed Web of Science ®Google Scholar

Nahirney M, Chaput K, Metcalfe A. Assessing the role of maternal race on the prediction of NICU admission by three growth charts: a cross-sectional study. J Matern-Fetal Neonatal Med. 2021;34(8):1233–1240. DOI:10.1080/14767058.2019.1631791.

 PubMed Web of Science ®Google Scholar

Morales-Roselló J, Cañada Martínez AJ, Scarinci E, et al. Comparison of cerebroplacental ratio, intergrowth-21st standards, customized growth, and local population references for the prediction of fetal compromise: which is the best approach? Fetal Diagn Ther. 2019;46(5):341–352. DOI:10.1159/000497142.

 PubMed Web of Science ®Google Scholar

Savirón-Cornudella R, Esteban LM, Tajada-Duaso M, et al. Detection of adverse perinatal outcomes at term delivery using ultrasound estimated percentile weight at 35 weeks of gestation: comparison of five fetal growth standards. Fetal Diagn Ther. 2020;47(2):104–114. DOI:10.1159/000500453.

 PubMed Web of Science ®Google Scholar

Vikraman S, Elayedatt R. Prospective comparative evaluation of performance of fetal growth charts in the diagnosis of suboptimal fetal growth during third trimester ultrasound. J Fetal Med. 2020;07(02):103–110. DOI:10.1007/s40556-020-00244-9.

 Google Scholar

Lorusso L, Kato DMP, Dalla Costa NRA, et al. Performance of local reference curve on the diagnosis of large for gestational age fetuses in diabetic pregnant women. J Matern Fetal Neonatal Med. 2022;35(10):1899–1906. DOI:10.1080/14767058.2020.1774539.

 PubMed Web of Science ®Google Scholar

Choi SKY, Gordon A, Hilder L, et al. Performance of six birthweight and estimated fetal weight standards for predicting adverse perinatal outcomes: a 10-year nationwide population-based study. Ultrasound Obstet Gynecol. 2021;58(2):264–277. DOI:10.1002/uog.22151.

 PubMed Web of Science ®Google Scholar

Hiersch L, Lipworth H, Kingdom J, et al. Identification of the optimal growth chart and threshold for the prediction of antepartum stillbirth. Arch Gynecol Obstet. 2021;303(2):381–390. DOI:10.1007/s00404-020-05747-4.

 PubMed Web of Science ®Google Scholar

Savirón-Cornudella R, Esteban LM, Aznar-Gimeno R, et al. Prediction of large for gestational age by ultrasound at 35 weeks and impact of Ultrasound-Delivery interval: comparison of 6 standards. Fetal Diagn Ther. 2021;48(1):15–23. DOI:10.1159/000510020.

 PubMed Web of Science ®Google Scholar

Kato DMP, Lorusso L, Bruns RF, et al. Performance of a local reference curve for predicting small for gestational age fetuses in pregnant women with HIV/AIDS. J Clin Ultrasound. 2021;49(4):322–327. DOI:10.1002/jcu.22961.

 PubMed Web of Science ®Google Scholar

Sovio U, Smith GCS. Comparison of estimated fetal weight percentiles near term for predicting extremes of birthweight percentile. Am J Obstet Gynecol. 2021;224(3):292.e1–292.e19. e1-292.e19. DOI:10.1016/j.ajog.2020.08.054.

 PubMed Web of Science ®Google Scholar

Melamed N, Hiersch L, Aviram A, et al. Diagnostic accuracy of fetal growth charts for placenta-related fetal growth restriction. Placenta. 2021;105:70–77. DOI:10.1016/j.placenta.2021.01.022.

 PubMed Web of Science ®Google Scholar