Increased ovulation after bariatric surgery in women with polycystic ovary syndrome


Women with polycystic ovary syndrome experience increased ovulation after bariatric surgery according to the findings of research published in the scientific journal, The Lancet.

Polycystic ovary syndrome (PCOS) affects how women’s ovaries work. The follicles in polycystic ovaries often do not release an egg so ovulation does not happen. This can lead to irregular periods and difficulties with becoming pregnant.

Obesity complicates issues with fertility in women with PCOS even further. This study compared ovulation rates in women with PCOS and obesity after bariatric surgery versus best usual medical care.

80 women aged 18 years and older, with a diagnosis of PCOS and obesity (body mass index of 35 kg/m2 or higher), were randomly allocated to either a vertical sleeve gastrectomy, a popular form of bariatric surgery or best usual medical care with behavioural interventions.

Over the next 52 weeks, the team monitored ovulation in these women using a blood test to measure levels of the hormone, progesterone. Bariatric surgery was shown to be more effective than medical care for the induction of spontaneous ovulation in women with PCOS, obesity, and irregular and inconsistent menstrual blood flow (oligomenorrhoea) or no menstrual periods (amenorrhoea). 

Women in the surgical group had 2.5 times more spontaneous ovulations compared with the medical group. The findings indicate that bariatric surgery is likely to improve the prospects of spontaneous fertility in women with PCOS and obesity.

Commenting on the significance of the findings, co-author and Conway Fellow, Professor Carel le Roux said, “This randomized control trial showed increased ovulation after bariatric surgery in women with polycystic ovarian syndrome, partly explaining why we see increased fertility after bariatric surgery. This is the biggest step forward since bariatric surgery was shown to put type 2 diabetes into remission for the field.”

Prof. Carel le Roux is Professor of Chemical Pathology, UCD School of Medicine, UCD Diabetes Complications Research Centre, St Vincent’s University Hospital, and the National Maternity Hospital. The research study is a collaboration between Ulster University, Imperial College London, and UCD with participants recruited through two UK based academic clinical centres.

The findings are available online:

Journal citation: 
Samarasinghe, Suhaniya N S et al. Bariatric surgery for spontaneous ovulation in women living with polycystic ovary syndrome: the BAMBINI multicentre, open-label, randomised controlled trial. The Lancet 2024.