Menstrual and Reproductive Function Before and After Metabolic Bariatric Surgery

To evaluate the impact of metabolic bariatric surgery on menstrual function, hormonal profiles, and reproductive health in women of reproductive age.

In this prospective cohort study, women aged 18-45 years undergoing Roux-en-Y gastric bypass or sleeve gastrectomy were recruited from a UK bariatric centre and followed for up to 24 months. Control participants were women with obesity receiving non-surgical weight management. Participants consented to clinical, biochemical, ultrasonographic, and questionnaire-based assessments of menstruation and pregnancy intentions.

Eighty-four women underwent surgery (49 bypass, 35 sleeve); 18 controls without surgery. By 24 months, 15 were lost to follow-up; mean excess weight loss was 64-73% with no difference between procedures. Anti-Mullerian Hormone (AMH) (n = 33) decreased post-surgery (16.6 to 16.0 pmol/L; P < 0.001); sex hormone-binding globulin (SHBG) increased (30.6 to 66.8 nmol/L; P < 0.001), and free androgen index (FAI) decreased (3.92 to 1.84; P < 0.001). Irregular menstruation and hirsutism decreased. Among 66 women with baseline transvaginal ultrasound scans, 33% had polycystic ovarian morphology, reducing to 10% postoperatively (n = 17); ovarian volume decreased significantly. At baseline (n = 76), 31% of surgical participants expressed a desire for pregnancy. Twenty pregnancies occurred, most 12-24 months post-surgery.

Metabolic bariatric surgery was associated with > 30 kg weight loss by 24 months, reduced FAI, and improvements in menstrual regularity, and ovarian morphology, suggesting potential improvement in fertility-related parameters. Given high pregnancy intention, findings support the need for integrated reproductive counselling and preconception care within bariatric pathways.