Choice of stimulation in polycystic ovarian syndrome: the influence of obesity.

Obesity modifies insulin sensitivity and gonadotrophins dynamics, and is associated with disorders of spontaneous ovulation. High concentrations of leptin are possibly a link between weight and spontaneous ovulation. Weight excess in polycystic ovary syndrome (PCOS) patients increases hyperinsulinaemia, which may result in altered follicular maturation. Obese PCOS women are characterized by a decreased efficiency of the different stimulation treatments. Although clomiphene resistance is not associated with obesity, the dose of clomiphene required to achieve ovulation is positively correlated with body weight. Obese PCOS women also require higher doses of gonadotrophins than their lean counterparts, with ultimately poorer results in pulsatile gonadotrophin releasing hormone-stimulated cycles. The first stage in the optimal management of obese PCOS anovulatory women is a weight loss programme, which helps to correct the clinical and endocrine abnormalities.