Metformin may not improve pregnancy outcomes for obese women
medwireNews: The authors of a systematic review find insufficient evidence to support the use of metformin to improve pregnancy outcomes among obese women.
As reported in The Cochrane Library, Jodie Dodd, from the University of Adelaide in South Australia, and colleagues analyzed data from three placebo-controlled randomized trials assessing metformin use during pregnancy. The trials included a total of 1099 women with a BMI of at least 30 kg/m2, and the dose of metformin ranged from 500 mg twice daily to 3 g/day.
The team found that women who received metformin during pregnancy had a similar risk for their baby being born large for gestational age – defined as birthweight above the 90th centile for gestational age and infant sex – as those treated with placebo, with a risk ratio (RR) of 0.95.
Furthermore, there was “little or no difference” in the risk for preeclampsia, gestational diabetes, and gestational hypertension between the two groups, and rates of preterm premature rupture of membranes, shoulder dystocia, and postpartum hemorrhage were comparable, report Dodd and team.
Infant outcomes such as neonatal intensive care unit admission, hypoglycemia, hyperbilirubinemia, and perinatal death also occurred at similar rates among babies born to mothers treated with metformin or placebo.
The researchers did, however, find that women who were treated with metformin had a “slightly lower” degree of gestational weight than those given placebo, with an average difference of 2.60 kg.
Participants given metformin were significantly more likely to experience diarrhea than those in the placebo group (RR=2.34), but there was no significant difference in the rates of abdominal pain or headache between the two groups.
Together, these findings indicate that at present, “[t]here is insufficient evidence to support the use of metformin for women with obesity in pregnancy for improving maternal and infant outcomes,” say the study authors.
They note that “[t]he quality of the evidence in this review varied from high to low,” and that only a small number of studies were eligible for inclusion.
“Furthermore, none of the included studies included women categorised as ‘overweight’ and no trials looked at metformin in combination with another treatment,” Dodd and colleagues add.
And the team concludes: “Future research is required in order to further evaluate the role of metformin therapy in pregnant women with obesity or who are overweight, as a strategy to improve maternal and infant health, alone or as an adjuvant to dietary and lifestyle advice.”
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