Bariatric surgery, also known as weight loss surgery, can indirectly improve fertility in individuals with polycystic ovary syndrome (PCOS) by addressing obesity, which is a common comorbidity associated with PCOS.
Women who underwent surgery lost significantly more weight at 52 weeks vs. medical therapy, with a mean difference between groups of –29.1 kg (95% CI, –37.5 to –20.8). Researchers also observed significant between-group differences favoring surgery for HbA1c, systolic and diastolic blood pressure, fasting glucose, triglycerides and LDL cholesterol, as well as improvements in depression and anxiety scores that favored bariatric surgery.
1. Weight loss: PCOS is often associated with obesity or being overweight, which can exacerbate the symptoms of PCOS, including infertility. Bariatric surgery, such as gastric bypass or sleeve gastrectomy, leads to significant and sustained weight loss by restricting the amount of food the stomach can hold and/or altering the absorption of nutrients.
2. Improvement in hormonal imbalances: Obesity can worsen the hormonal imbalances seen in PCOS, such as high levels of androgens (male hormones) and insulin resistance. Significant weight loss achieved through bariatric surgery can help improve these hormonal imbalances, leading to a restoration of normal ovulatory cycles and increased chances of conceiving naturally.
3. Reduction in insulin resistance: PCOS is strongly linked to insulin resistance, which can contribute to infertility. Bariatric surgery has been shown to improve insulin sensitivity and reduce insulin resistance, thereby improving ovulation and increasing the chances of successful conception.
4. Restoration of menstrual regularity: Women with PCOS often experience irregular menstrual cycles or amenorrhea (absence of menstruation), which can make it difficult to conceive. Weight loss after bariatric surgery can help restore regular menstrual cycles, increasing the chances of ovulation and conception.
5. Improvement in ovulation: Obesity and the associated hormonal imbalances in PCOS can disrupt ovulation, making it difficult to conceive naturally. Weight loss achieved through bariatric surgery can help restore normal ovulatory function, increasing the chances of successful conception.
It's important to note that while bariatric surgery can improve fertility in individuals with PCOS, it is not a guaranteed solution. Some individuals may still require additional fertility treatments, such as ovulation induction medications or assisted reproductive technologies like in vitro fertilization (IVF), even after weight loss surgery. Additionally, bariatric surgery is typically recommended for individuals with a body mass index (BMI) of 40 or higher, or a BMI of 35 or higher with obesity-related comorbidities like PCOS.
Ref:
https://www.healio.com/news/endocrinology/20200721/women-with-pcos-have-high-pregnancy-live-birth-rates-after-bariatric-surgery 
