Oral Agents for Ovulation Induction

Abstract

Infertility due to ovulation disorders is 25% of all infertility causes. The most common cause of ovulation disorders is patients with normogonadatropic normogonadism, which is group II according to the World Health Organization anovulation classification and mostly consists of patients with polycystic ovary syndrome which affects 6-20% of women of reproductive age. Oral ovulation induction agents are a suitable option only for patients in this group. The purpose of the ovulation induction is to stimulate the ovaries for monofollicular development. Oral agents used in ovulation induction can be divided into two groups, selective estrogen receptor modulators and aromatase inhibitors as first-line agents, and metformin and inositols as second-line agents. The aim of this review is to compare the use and efficacy of the primary oral ovulation induction agents, clomiphene citrate and letrozole, and also to reveal the contributions of the adjuvant drugs metformin and inositol. It is seen that letrozole is superior to clomiphene citrate in polycystic ovary syndrome and is currently preferred as the first-choice drug worldwide. Metformin alone increases the ovulation rate compared to placebo in women with polycystic ovary syndrome, but should not be used as first-line therapy for anovulation. Similarly, when inositol is used alone, it does not increase the pregnancy rate.