Anovulation Or failure to ovulate is an important cause of Infertility, the commonest cause is PCOS. This can be tackled with lifestyle and weight management, also using ovulation induction drugs and insulin sensitisers as required. The commonest drug used is Clomiphene. If patients are Clomiphene resistant, they can be put on Letrozole. Some patients would require additional gonadotropins for ovulation. A few patients may not respond even to high doses of gonadotropins suggesting an FSH receptor defect. Patients with poor ovarian reserve would require additional DHEA along with ovulation induction drugs