Letrozole as first-line drug for ovulation induction in treatment-naïve infertile polycystic ovarian syndrome women

Objective One in seven couples is infertile and ovulatory dysfunction accounts for 25% of the cases. Polycystic ovarian syndrome (PCOS) is the most common endocrinopathy associated with ovulatory dysfunction. Traditionally, clomiphene is considered the first-line drug for infertile PCOS women. Recently, letrozole was found to be an effective alternative ovulogen. The recent Cochrane review concluded that although live birth was higher with letrozole in unselected PCOS population, evidence was insufficient regarding effect of letrozole in treatment-naive women. Materials and methods We conducted a cohort study that included treatment-naive infertile PCOS women at a tertiary level infertility center in South India. Participants in the prospective arm were given letrozole 2.5 mg daily for 5 days and the retrospective arm included women who had undergone ovulation induction with clomiphene (100 mg) for up to five treatment cycles. The primary outcome was ovulation rate. Secondary outcomes were clinical pregnancy, live birth, multiple pregnancy, and miscarriage rate. The trial was registered under the Clinical Trials Registry, India (CTRI/2018/07/014704). Results A total of 135 women in the letrozole group and 127 women in the clomiphene group underwent treatment. The ovulation rate per woman was similar in both groups (84.4% vs. 77.2%; p = 0.13). Letrozole was associated with significantly higher clinical pregnancy (38.5% vs. 22.0%; p = 0.004) and live birth rate per woman (30.3% vs. 18.9%; p = 0.03). Conclusion The current study found letrozole to be a superior ovulation induction agent as compared to clomiphene in treatment-naive infertile women with PCOS.