0
0
A new study raises concerns that taking the widely used anti-diabetes drug metformin during pregnancy could potentially hinder fetal development, including a slowing of kidney growth. The drug, commonly prescribed to manage blood sugar levels in individuals with diabetes, has been used during pregnancy to mitigate the risks associated with gestational diabetes and pre-diabetes.
Led by researchers from Baylor College of Medicine in the United States, the study, published in the American Journal of Obstetrics and Gynecology, found that metformin may have unexpected consequences on fetal growth, despite its effectiveness in controlling maternal blood sugar levels. The research team used an experimental primate model to explore how the drug affects fetal development when administered early in pregnancy.
The study involved 13 pregnant female rhesus monkeys who were given metformin daily, with doses equivalent to those typically prescribed to humans. The drug was administered starting within 30 days of conception, and on the 145th day of pregnancy, the researchers performed a caesarean section to deliver the fetuses and examine their development.
Results showed that metformin easily passed through the placenta and accumulated in the fetal kidneys, liver, intestines, placenta, amniotic fluid, and urine—at levels similar to those found in the mother. This accumulation of the drug was associated with restricted fetal growth, particularly in the kidneys, liver, heart, skeletal muscle, and fat deposits, all of which are crucial for proper fetal development. The overall result was a noticeable reduction in fetal body weight.
“Our study demonstrates fetal bioaccumulation of metformin with associated fetal growth restriction and renal dysmorphology after maternal initiation of the drug within 30 days of conception in primates,” the study’s authors noted.
While the researchers emphasize that metformin has not been linked to birth defects, they pointed out that the fetus lacks the ability to eliminate the drug as effectively as the mother. Unlike many other drugs that undergo “first-pass” metabolism in the liver—where their concentration is reduced before entering the bloodstream—metformin does not experience this effect. Instead, it is transported directly across the placenta, exposing the fetus to a dose similar to what the mother receives.
Jed Friedman, a co-author of the study and associate vice provost for diabetes programs at the University of Oklahoma Health Sciences, explained, “Metformin does not experience the first-pass effect; rather, it is transported across the placenta, exposing the fetus to an adult dose of the drug.”
The study also examined the impact of different maternal diets on the effects of metformin. Half of the pregnant primates were fed a conventional diet with 15% of their calories from fat, while the other half consumed a high-fat diet with 36% of their calories from fat. However, the researchers found that the drug’s levels in the fetus did not differ based on the diet.
Despite the significant findings, the study’s small sample size calls for further investigation. The researchers stressed the need for more studies to fully understand the long-term effects of metformin on fetal development and childhood health.
In light of these findings, health professionals may need to reconsider the use of metformin during pregnancy, especially for women who are not at high risk of diabetes-related complications. More research is needed to clarify whether the benefits of using the drug outweigh the potential risks for fetal growth and development.
