← Metformin × pregnancy & neonatal

SynthesisThe Cochrane database of systematic reviews2017

Oral anti-diabetic agents for women with established diabetes/impaired glucose tolerance or previous gestational diabetes planning pregnancy, or pregnant women with pre-existing diabetes.

Joanna Tieu et al.PubMed ↗Full text ↗Publisher ↗

  • Metforminlooks good hereLower pregnancy-induced hypertension, lower caesarean section, lower infant hypoglycaemia.Randomised, small.

What the trial testedrandomised · 707 people · 2017

Randomised vs insulin

Probably lowered pregnancy-induced hypertension

−42%−63% to −9%

metformin vs insulin

Bigger than 8 in 10 on the map

As reported

RR 0.58, 95% CI 0.37–0.91

Randomised vs insulin

Probably lowered caesarean section

−27%−39% to −12%

metformin vs insulin

Bigger than 6 in 10 on the map

As reported

RR 0.73, 95% CI 0.61–0.88

Randomised vs insulin

Probably lowered infant hypoglycaemia

−66%−82% to −38%

metformin vs insulin

Bigger than 7 in 10 for glycemic control

As reported

RR 0.34, 95% CI 0.18–0.62

Range includes no effect

No clear effect on pre-eclampsia

−37%−67% to +20%

metformin vs insulin

Bigger than 7 in 10 on the map

As reported

RR 0.63, 95% CI 0.33–1.20

+2 more in the walkthrough ↓

Who was studied, and how

988people in the Effect of Metformin on Healthy Live Birth After In-vitro Fertilization in Women With Prediabetes Mellitus trial, from 2024
707of them with gestational diabetes, in this paper

The trial randomly assignedassigned by chance

metformin
insulin

Probably lowered pregnancy-induced hypertension−42%

Probably lowered caesarean section−27%

Probably lowered infant hypoglycaemia−66%

randomised

the abstract, start to end

… for pre-eclampsia (risk ratio (RR) 0.63, 95% confidence interval (CI) 0.33 to 1.20; RCTs = 2; participants = 227; very low-quality evidence) although in one RCT women receiving metformin were less likely to have pregnancy-induced hypertension (RR 0.58, 95% CI 0.37 to 0.91; RCTs = 1; …

… with those receiving insulin (RR 0.73, 95% CI 0.61 to 0.88; RCTs = 3; …

… large-for-gestational-age infants (RR 1.12, 95% CI 0.73 to 1.72; RCTs = 1; …

… groups for induction of labour (RR 1.42, 95% CI 0.62 to 3.28; RCTs = 2; participants = 35; very low-quality evidence), though infant hypoglycaemia was reduced in the metformin group (RR 0.34, 95% CI 0.18 to 0.62; RCTs = 3; …

← favours treatmentfavours comparator →
could be chance
Pre-eclampsiametformin vs insulin
RR 0.630.33–1.20
Pregnancy-induced hypertensionmetformin vs insulin
RR 0.580.37–0.91
Caesarean sectionmetformin vs insulin
RR 0.730.61–0.88
Large-for-gestational-age infantsmetformin vs insulin
RR 1.120.73–1.72
Induction of labourmetformin vs insulin
RR 1.420.62–3.28
Infant hypoglycaemiametformin vs insulin
RR 0.340.18–0.62
MetforminGlycemic controlBlood pressureCardiovascular eventsPregnancy & neonatal
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8 papers cite it

2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
this paperpooled itcites it

The trial

NCT06064669988 enrolled2024
Full record →Abstract, authors, funding and every citing paper · PMID 29045765