Clomiphene Citrate versus Letrozole for Induction of Ovulation in Infertile women having Polycystic Ovarian Syndrome (Randomized Controlled Trial)

Background: Polycystic ovary syndrome is a disorder but with unclear etiology that its diagnosis depends on exclusion of other etiologies with ovulatory disorders and androgen excess as congenital adrenal hyperplasia, 21-hydroxylase deficient non classic congenital adrenal hyperplasia (NCAH), adrenal or ovarian androgen-secreting tumors, disorders of adrenocortical dysfunction as Cushing’s disease, and abuse of androgenic or anabolic drugs. Polycystic ovary syndrome affects approximately 6-15% of women in reproductive age and constitutes 50% of the causes of infertility in women. Aim of the Work: To compare the efficacy of letrozole on ovulation induction to that of clomiphene citrate in women suffering polycystic ovary syndrome and the effect on the follicular maturation, endometrial thickness and pregnancy rate. This study was carried in the outpatient infertility clinic of Ain-Shams Maternity Hospital during the period from November 2020 till April 2021. Patients and Methods: This study included 80 infertile women diagnosed as having polycystic ovary syndrome. Women were randomized into two groups. Letrozole group (1) included 40 women who were given the aromatase inhibitor (Letrozole) orally in a 5mg dose daily from day 3 to day 7 of the menstrual cycle. While Clomiphene citrate group (2) included 40 women who were given the clomiphene citrate orally in 100mg dose daily from day 3 to day 7 of the menstrual cycle. All women were counseled and informed consent was obtained before recruitment. Results: In this study, ovulation rate was significantly more frequent in the Letrozole group (82.5%, 33 women reached ovulation successfully) than in Clomiphene citrate group (60%, 24 women reached ovulation successfully) within P value=0.024. Clomiphene citrate at a dose of 100mg showed more efficacies in the number of follicle ≥18mm than Letrozole at a dose of 5mg. In Letrozole group, the number of follicles (≥18mm in diameter) ranged from 1 to 2 with a Mean±SD= 1.4±0.65 and in Clomiphene citrate group, the number of follicles (≥18mm in diameter) ranged from 1 to 3 with a Mean±SD= 1.9± 0.41 (P value=0.0001). Conclusion: Letrozole can be considered as a first line treatment of anovulation in polycystic ovary syndrome. But, moreover studies including larger number of cases will further confirm the efficacy of letrozole versus clomiphene citrate in induction of ovulation, reaching to the optimum doses for aromatases inhibitors, more observation on endometrial thickness, incidence of pregnancy outcomes, incidence of abortion and incidence of congenital fetal malformations.