Diabetes Drug İncrease in Birth Defects
Men's use of diabetes drug just before conception is linked to a 40% increase in birth defects, study finds
Metformin use by men in the three-month period before they conceived a child was linked to a 40% higher risk of birth defects in the offspring, according to a study published Monday in the journal Annals of Internal Medicine.
Metformin is a first-line drug in the treatment of type 2 diabetes.
The research, which was done out of Denmark, used national registries to follow over 1 million births between 1997 and 2016 and compared the risk of major birth defects in babies based on paternal exposures to diabetes medications. The study observed only children who were born to women under 35 and men under 40. Babies born to women with diabetes were excluded.
The researchers considered men exposed to metformin if they filled a prescription for it in the three months before conception, which is how long it takes the fertilizing sperm to fully mature.
The researchers did not find any significant association between birth defects and paternal exposure to diabetes medication other than metformin.
However, the authors note that they did not have data on other aspects of diabetes, such as glycemic control or medication compliance, as they assessed data only on when prescriptions were filled. In addition, babies who had paternal metformin exposure also tended to have parents who were older and of a lower socioeconomic status, which may play a role.
In an editorial published alongside the study, Germain Buck Louis, a reproductive and perinatal epidemiologist at George Mason University who was not involved in the research, said there is evidence from past studies to suggest that “altered testosterone levels may be an underlying mechanism raising concern about the antiandrogenic activity of oral diabetes pharmacologic agents, including metformin” to explain these findings.