Differences in neonatal adverse outcomes among women with gestational diabetes mellitus managed by diet or medication: a propensity score matched analysis of a population-based sample

Figures & data

Figure 1. Flowchart maternity data 2010–2017.

Table 1. Maternal characteristics by variables accounted for in the propensity score: before and after matching.

	Unmatched sample (Overall sample n = 930)					PS matched sample (Overall n = 710)
	n	Medicated GDM	Diet controlled GDM	OR^a(95% CI)	d	n	Medicated GDM	Diet controlled GDM	OR^b(95% CI)	d
N (%)	930	411 (44.2)	519 (55.8)	–	–	710	355 (50.0)	355 (50.0)	–	–
Mother’s age [mean (SD)]	930	31.4 (5.9)	30.4 (5.8)	0.97 (0.95–0.99)^c	0.17	710	31.0 (5.9)	30.7 (5.7)	0.99 (0.96–1.01)	−0.07
BMI categories [kg/m^2], %
≤24.9	197	14.1	26.8	1.00	−0.32	109	16.1	14.6	1.0	−0.01
25.0-29.9	210	21.6	23.3	0.57 (0.38–0.86)^c	−0.04	167	22.8	24.2	1.20 (0.71–2.05)	0.05
30.0-34.9	231	28.5	22.0	0.41 (0.27–0.61)^^	0.15	194	27.6	27.0	1.10 (0.65–1.86)	0.01
≥35.0	292	35.8	27.9	0.41 (0.28–0.60)^^	0.17	240	33.5	34.1	1.15 (0.69–1.92)	−0.04
Born outside of Australia, %	135	16.5	12.9	1.34 (0.93–1.93)	−0.10	105	14.6	14.9	0.98 (0.65–1.47)	−0.05
Aboriginal or Torres Strait Islander, %	46	3.9	5.8	1.57 (0.84–2.91)	−0.09	37	4.5	5.9	1.31 (0.68–2.51)	0.06
SEIFA score, continuous [mean (SD)]	930	963.3 (49.1)	960.5 (49.3)	0.99 (0.99–1.99)	0.06	710	963.1 (49.8)	961.1 (50.2)	0.99 (0.99–1.00)	−0.01
History of gestational diabetes, %	276	29.7	29.7	0.99 (0.75–1.32)	0.00	215	31.3	29.3	0.90 (0.64–1.26)	0.00
Current or past smoker, %	165	13.9	20.8	1.60 (1.13–2.26)^c	−0.18	103	14.9	14.1	0.93 (0.59–1.44)	−0.03
Hypertension, %	31	5.3	1.7	0.31 (0.14–0.68)^c	0.20	21	3.4	2.5	0.67 (0.24–1.87)	0.06
Pregnancy induced hypertension, %	59	7.1	5.8	0.81 (0.48–1.36)	0.05	46	5.9	7.0	1.19 (0.67–2.13)	0.02
Polycystic ovarian syndrome, %	91	11.9	8.1	0.65 (0.42–1.00)	0.13	75	10.4	10.7	1.03 (0.62–1.71)	0.08
Pre-eclampsia or eclampsia, %	32	3.6	3.3	0.95 (0.47–1.90)	0.02	23	3.4	3.1	0.92 (0.40–2.08)	0.02
Pyrexia during pregnancy, %	54	4.9	6.5	1.37 (0.78–2.42)	−0.07	37	5.6	4.8	0.85 (0.44–1.62)	−0.01
Parity, %
0	345	32.8	40.5	1.00	−0.16	257	35.2	37.2	1.0	−0.01
1	302	37.0	28.9	0.65 (0.48–0.89)^c	0.17	237	33.5	33.2	0.92 (0.62–1.36)	0.05
2	160	18.5	16.2	0.72 (0.49–1.05)	0.06	133	18.9	18.6	0.92 (0.59–1.44)	−0.02
≥3	123	11.7	14.4	1.01 (0.67–1.55)	−0.08	83	12.4	11.0	0.83 (0.51–1.37)	−0.04

^aOdds ratios derived from bivariate logistic regressions constructed on the unmatched sample.

^bOdds ratios derived from bivariate conditional logistic regressions constructed on the matched sample.

^cP value ≤0.05 and >0.001; ^{^}P value ≤0.001.

CI: confidence interval; d: standardized difference; OR: odds ratio; PS: propensity score.

Figure 2. Standardized differences before and after propensity score matching by study variables included in the construction of the propensity score.

Table 2. Conditional logistic regression^! comparing neonatal outcomes in women with and without medically managed GDM (medicated group as reference) following PS matching.

Neonatal outcome^b	OR (95% CI)	p Value
Birth injury	3.50 (1.62 − 7.58)	0.001
1-min Apgar score <7	1.31 (0.80 − 2.16)	0.277
5-min Apgar score <7	1.76 (0.57 − 5.43)	0.326
Shoulder dystocia	2.46 (0.45 − 13.53)	0.299
Hypoglycemia	1.56 (1.03 − 2.38)	0.037
Respiratory distress	1.44 (0.49 − 4.22)	0.510
Hypothermia	2.29 (1.05 − 5.00)	0.037
Jaundice	2.55 (0.56 − 11.70)	0.229
Small for gestational age	2.06 (1.01 − 4.18)	0.046
Large for gestational age	0.57 (0.35 − 0.95)	0.032
Admission to a special care unit	2.04 (1.29 − 3.21)	0.002
Not breastfeeding	0.92 (0.58 − 1.47)	0.742
Feeding problems	0.58 (0.17 − 1.93)	0.374

^aIn addition to the variables included in the construction of the propensity score, the conditional regression also adjusted for gestational age at delivery, induction of labor, birth type, and number of ultrasounds conducted during the pregnancy.

^bEach neonatal outcome was modeled separately.

Saccone G, Khalifeh A, Al-Kouatly HB, et al. Screening for gestational diabetes mellitus: one step versus two step approach. A meta-analysis of randomized trials. J Matern Fetal Neonatal Med. 2020;33(9):1616–1624. doi:10.1080/14767058.2018.1519543.

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Data availability statement

All data generated or analyzed during this study are included in this published article (and its supplementary information files).