Clomiphene citrate versus letrozole for ovulation induction in anovulatory infertility: a prospective study

Ovulatory dysfunction is a common problem and is responsible for about 40% cases of female infertility. It manifests as amenorrhea, oligomenorrhea or polymenorrhea with painless periods. Recent years have seen a significant rise in number of women presenting with chronic anovulation due to ovulatory dysfunction. PCOS is the most common cause of infertility due to chronic anovulation. Using the Rotterdam criteria, a clinical diagnosis of PCOS is easily reached and most often treatment can be initiated following a few basic investigations and exclusion of other female and male factors responsible for infertility. Hypothyroidism is another common cause of anovulation and infertility. Other causes of anovulation include hyperprolactinemia, pituitary causes, hypothalamic causes, obesity, premature ovarian failure, extreme exercises etc. A large subset of patients with amenorrhea or oligomenorrhea and chronic anovulation seek care because they are unable to conceive. The goal of ovulation induction refers to the therapeutic restoration of the release of one egg per cycle in a woman who either has not been ovulating regularly or has not been ovulating at all. Various drugs are used for induction of ovulation e.g. clomiphene citrate (CC), letrozole (let), human menopausal gonadotropin (HMG), follicle stimulating hormone (FSH), gonadotropin releasing hormone (GnRH) agonists etc. Gonadotropins are more effective than CC but are expensive and associated with higher risk of ovarian hyperstimulation ABSTRACT