The diabetes drug, metformin has been found to reduce maternal weight gain in obese pregnant women without diabetes, but not infant birth weight, according to the results of a randomized clinical trial.
The British researchers found that the drug could help reduce maternal weight gain and cut the risk of a potentially dangerous complication called preeclampsia. The study also adds to evidence that metformin does not curb obese women's risk of having an abnormally large newborn.
‘The use of diabetes drug, metformin was associated with reduced maternal weight gain and a lower incidence of preeclampsia in obese pregnant women.
Metformin is an oral diabetes drug used to treat type 2 diabetes. Sometimes, the drug is given to women with gestational diabetes, in which the fetus will grow large enough to complicate childbirth or require a cesarean section delivery.
"Those findings bring to light some potential benefits of metformin for obese women," said Dr Jerrie Refuerzo, an associate professor of obstetrics and gynecology at the University of Texas Health McGovern Medical School, in Houston.
Diet and exercise are the only keys to managing obesity during pregnancy, said Dr Refuerzo, who was not involved in the study.
Obese pregnant women often give birth to large newborns, even if they do not have diabetes. This is because their blood sugar levels are elevated, explained Dr. Hassan Shehata, the senior researcher on the new study. He is an obstetrician-gynecologist at Epsom and St. Helier University Hospitals, in London.
Dr Shehata's team hoped that metformin would lower the odds of obese pregnant women having a large baby.
About 450 British women, who between their 12th and 18th weeks of pregnancy participated in the randomized trial. All the participants were severely obese, with a body mass index of 35.
One group of women were given 3-gram dose of metformin every day, and the other were given a placebo.
Among the women given metformin, almost 17% had a risk of having a large baby with birth weight at least in the 90th percentile. That compared with just over 15 % of women who were given the placebo.
However, metformin did curb women's weight gain. The participants typically gained nearly 4 pounds less than placebo users did.
Women on metformin also had a substantially lower risk of preeclampsia -- with 3% developing it, versus 11% of placebo users.
Preeclampsia, which occurs after the 20th week of pregnancy, is marked by high blood pressure and other signs that a woman's organs -- such as the kidneys and liver -- are not functioning properly. It can cause preterm delivery and low birth weight, and can raise a woman's risk of seizures and coma.
"Preeclampsia is one of the important pregnancy complications that we've been trying to reduce for decades, with variable success," said Shehata.
It's estimated that 20 % of pregnant women in the United Kingdom are obese, Shehata noted. The study is published in the New England Journal of Medicine.