Table 4.

Summary of meta-analyses investigating the comparative effects of metformin administration during pregnancy in relation to alternative treatment options.

Meta-Analysis Outcomes	Summary of Results
Maternal outcomes §	Lower gestational weight gain (mean difference 1.57 kg  ±  0.60 kg) Lower risk of any hypertensive disease of pregnancy (including pre-eclampsia) (odd ratio 0.76, 95% CI 0.60–0.95) Higher risk of gastrointestinal side-effects (odds ratio 2.43, 95% CI 1.53–3.84) No difference in risk of preterm birth (spontaneous or iatrogenic) (odds ratio 0.90, 95% CI OR 0.67–1.21) No difference in risk of delivery by caesarean section (odds ratio 0.90, 95% CI 0.82–1.00) Lower risk of maternal hypoglycemia (odds ratio 0.47, 95% CI 0.28–0.80)
Neonatal outcomes ‡	Lower neonatal birthweight (mean difference −73.92 g, 95% CI −114.79–−33.06 g) Lower risk of neonatal macrosomia (OR 0.60, 95% CI 0.45–0.79) No difference in neonatal abdominal circumference (mean difference 0.00 cm, 95% CI −0.44–0.44 cm)
Children outcomes ‡	At 2 years of age Higher infant bodyweight (mean difference 440 g, 95% CI 50–830) No difference in infant height (mean difference 0.65 cm, 95% CI −1.31–2.61) At 5–9 years of age No difference in childhood bodyweight (mean difference 1.13 kg, 95% CI −0.19–2.45) No difference in childhood height (mean difference 0.02 cm, 95% CI −1.46–1.50) Higher childhood BMI (mean difference 0.78 kg/m2, 95% CI 0.23–1.33)

^§ Metformin vs. other treatments or placebo for any indication of administration (i.e., PCOS, obesity, or management of GDM) [88]; ^‡ Metformin vs. insulin for the management of GDM [103].