Birth control pills, either used alone or in combination with the drug metformin, do not increase the risk of metabolic syndrome—a condition that can lead to heart disease and diabetes—in women with polycystic ovary syndrome (PCOS), even among those who are overweight. This conclusion comes from a study conducted by researchers at the Perelman School of Medicine at the University of Pennsylvania and published in PLOS Medicine.
The research addresses ongoing concerns about whether oral contraceptives might raise cardiovascular or diabetes risks for women with PCOS. "Our results can help guide treatment decisions right away," said Anuja Dokras, MD, PhD, MHCI, director of the Penn Polycystic Ovary Syndrome Center and the Founder’s Professor of Women’s Health in the Department of Obstetrics and Gynecology at Penn. "Oral birth control remains a safe and effective first-line option for managing PCOS symptoms, and our research showed providers can prescribe it alone with greater peace of mind knowing that it’s safe and effective for these higher risk patients. Patients should also know birth control helped improve emotions and did not cause weight gain."
PCOS is a hormonal disorder affecting approximately 5-6 million women in the United States and is a leading cause of female infertility. It disrupts communication between brain hormones and the ovaries, causing an overproduction of androgen hormones. Symptoms may include irregular periods, weight gain, acne, excess hair growth, and an increased likelihood of developing metabolic syndrome.
Doctors often recommend oral contraceptives to manage PCOS symptoms but have worried that such medications could worsen cardiovascular or diabetes risk factors due to their impact on insulin resistance, blood sugar levels, blood pressure, and fat distribution. These concerns are heightened for overweight women already facing elevated health risks. As a result, metformin—a medication commonly used to treat type 2 diabetes—has frequently been prescribed alongside birth control pills.
In this study led by Dokras’ team, 240 women with PCOS and high body mass index were randomly assigned to receive either birth control pills, metformin alone, or both treatments for 24 weeks. At the end of this period, there was no significant difference in rates of metabolic syndrome among any of the groups.
Additionally, participants taking birth control pills experienced modest reductions in weight, waist circumference, and abdominal fat compared to their baseline measurements. Metformin alone did not reduce metabolic syndrome risk but was linked to frequent gastrointestinal side effects such as diarrhea. Those on metformin—either by itself or combined with birth control—were more likely to miss doses because of these side effects.
"Physicians can help patients simplify and personalize treatment while balancing the impact of medications on people’s quality of life," said Dokras.
Previous studies typically focused on individual cardiovascular risk factors rather than metabolic syndrome as a whole. According to Dokras, longer-term studies are needed to confirm these findings across broader populations and age ranges as well as evaluate additional outcomes like mental health impacts.
The study received funding from the National Institutes of Health Eunice Kennedy Shriver National Institute of Child Health and Human Development.
