Antenatal metformin does not benefit obese pregnant women: Lancet

Australia: Metformin gave in addition to dietary and lifestyle advice initiated at 10–20 weeks’ gestation does not improve pregnancy and birth outcomes in pregnant women who are overweight or obese, according to a new study published in the journal Lancet.

Maternal obesity and overweight are associated with complications in pregnancy. Although lifestyle and antenatal dietary interventions modestly affect gestational weight gain but have no effect on the pregnancy outcomes.

Jodie M Dodd, University of Adelaide, and Women's & Children's Hospital, North Adelaide, Australia, and colleagues conducted the GRoW study to assess the effects on maternal and infant outcomes of antenatal metformin given in addition to dietary and lifestyle advice among overweight and obese pregnant women.

GRoW was a multicentre, randomised, double-blind, placebo-controlled trial that recruited 524 pregnant women at 10–20 weeks’ gestation with a BMI of 25 kg/m² or higher from three public maternity units in Adelaide, Australia. Women were randomly assigned to receive either metformin (to a maximum dose of 2000 mg per day) or matching placebo via a computer-generated schedule in the ratio 1:1.

The primary outcome was the proportion of infants with birthweight greater than 4000 g. Secondary outcomes included measures of maternal weight gain, maternal diet and physical activity, maternal pregnancy and birth outcomes, maternal quality of life and emotional wellbeing, and infant birth outcomes. Outcomes were analysed on an intention-to-treat basis (including all randomly assigned women who did not withdraw consent to use their data, and who did not have a miscarriage or termination of pregnancy before 20 weeks’ gestation or a stillbirth). All women received an antenatal dietary and lifestyle intervention.

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Key Findings:

• There was no significant difference in the proportion of infants with birthweight greater than 4000 g (40 [16%] with metformin vs 37 [14%] with placebo.


• Women receiving metformin had lower average weekly gestational weight gain and were more likely to have gestational weight gain below recommendations.


• Total gestational weight gain, pregnancy and birth outcomes, maternal diet and physical activity, and maternal quality of life and emotional well-being did not differ significantly between groups.


• Similar numbers of women in both treatment groups (76% [159/208] in the metformin group and 73% [144/196] in the placebo group) reported side-effects including nausea, diarrhoea, and vomiting. Two stillbirths (placebo group) and one neonatal death (metformin group) occurred; none of the perinatal deaths were determined to be attributable to participation in the trial.

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"For pregnant women who are overweight or obese, metformin given in addition to dietary and lifestyle advice initiated at 10–20 weeks’ gestation does not improve pregnancy and birth outcomes," concluded the authors.

For further reference log on to https://doi.org/10.1016/S2213-8587(18)30310-3