Metabolic bariatric surgery improves menstrual cycle frequency and symptoms of polycystic ovaries in women living with obesity, a new study from the University of Surrey reports. The research team is recommending that preconception care and reproductive counselling be made available to women who undergo this weight loss surgery to help improve their reproductive health.

During this study, Surrey researchers investigated the impact of metabolic surgery on the menstrual cycle, hormones and reproductive health of women aged 18- 45 years old who lived with obesity. To learn more, researchers analysed data over the course of 24 months from 84 women who underwent bariatric surgery (49 gastric bypass and 35 gastric sleeve) and 18 women living with obesity who did not undergo surgery.

Researchers found that at 12 months and 24 months post-surgery, the average weight loss of women was more than 30 kilograms. Interestingly, post-surgery the number of women who had polycystic ovaries, which is known to affect fertility, was significantly reduced and persisted in only 10 per cent of women with the condition after 24 months. Women also reported a resolution of clinical hirsutism (excess body hair), a common symptom of polycystic ovaries, by 12 months.

The researchers also found that women who had previously experienced irregular periods reported a more regular cycle post-surgery.

A large proportion of those undergoing bariatric surgery are women of reproductive age, who may be planning a pregnancy in the coming years. So much remains unknown about the impact of this type of surgery on women who are planning to have children and raises the question of when the ideal time post-surgery is to conceive.”


Professor Martin Whyte, co-author of the study and Professor of Metabolic Medicine, University of Surrey

Women experience a higher prevalence of obesity than men, with 57 per cent of women in the UK classified as overweight and 27 per cent living with obesity, which can affect fertility and the health of an unborn baby.

In addition, researchers noted that following surgery, 17 women had healthy pregnancies. Although not specially examined in the study, no difference in birth weight was observed between babies conceived within or after the first year.

Dr Kathryn Hart, co-author of the study and Associate Professor in Nutrition and Dietetics at the University of Surrey, said:

“What we have found is that bariatric surgery positively affects the reproductive health of women living with obesity and can improve the likelihood of them having a healthy pregnancy post-surgery.

“Dysregulated hormone levels, irregular periods and conditions such as polycystic ovaries are impacted by obesity. By reducing this, what we have seen is that it can lead to improvements without the need for medication.

“We would suggest that clinicians consider medical intervention for obesity to treat irregularities in the menstrual cycle and issues with fertility.”

Source:

Journal reference:

Whyte, M., et al. (2026). Menstrual and Reproductive Function Before and After Metabolic Bariatric Surgery. Obesity Surgery. DOI: 10.1007/s11695-026-08852-6. https://link.springer.com/article/10.1007/s11695-026-08852-6