Metformin Use During Pregnancy and Maternal Outcomes

Pavankumar Kamat


May 05, 2021


  • Use of metformin for any indication during pregnancy was associated with a reduction in gestational weight gain (GWG) and a modest reduction in the risk of pre-eclampsia, but an increased risk of gastrointestinal (GI) side effects compared with other treatments.

  • No significant effects were observed on other maternal outcomes.

Why this matters

  • Despite the widespread use of metformin during pregnancy, limited data is available on maternal outcomes in metformin users.

Study design

  • UK researchers conducted a meta-analysis of 35 randomised controlled trials (RCTs) including 8033 participants.

  • Funding: None.

Key results

  • Metformin vs other treatment group had:

    • reduction in GWG (mean difference, 1.55 kg; 95% CI, -2.14 to -0.95; P<.00001; I2, 86%); and

    • lower risk of pre-eclampsia (OR, 0.69; 95% CI, 0.50-0.95; P=.02; I2, 55%).

  • No significant difference was seen between metformin and other treatment group in the risk of:

  • Metformin vs other treatment group was associated with an increased risk of GI side effects (OR, 2.43; 95% CI, 1.53-3.84; P=.0002; I2, 76%).


  • Heterogeneity among studies.


Tarry-Adkins JL, Ozanne SE, Aiken CE. Impact of metformin treatment during pregnancy on maternal outcomes: a systematic review/meta-analysis. Sci Rep. 2021;11(1):9240. doi: 10.1038/s41598-021-88650-5. PMID: 33927270. View full text

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.


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