New perspectives on ovulation induction with letrozole in women with polycystic ovary syndrome

Objective: To compare the efficacy and adverse event rates of letrozole in a stair-step and standard ovulation induction (OI) protocols in women with polycystic ovary syndrome (PCOS) and anovulatory infertility. Materials and methods: The study included 194 patients aged 28.7 (25;33), body mass index 21.5 (21;26) kg/m2. Of them, 106/194 (54.6%) women did not respond to the initial stimulation with 2.5 mg letrozole. They were divided into group 1 (n=52) and group 2 (n=54) undergoing stair-step protocol and standard protocol, respectively. During OI, the patients underwent ultrasound monitoring of ovarian and endometrial status. Furthermore, the clinical evaluation included estimated time of ovulation and ovulation and pregnancy rates. Results: The ovulation rates were equally high in both groups and was 92.3% on the stair-step protocol and 85.2% on the standard protocol (p=0.25). The time to ovulation was statistically significantly shorter in the stair-step protocol [33.9 (3.23) versus 59.5 (11.96) days; p<0.001]. The mean M echo was larger in the same group [0.2 (2.2) mm versus 9.3 (2.2) mm; p=0.01]. There was no statistical difference in pregnancy and live birth rates between the stair-step and standard protocols [17/52 (32.7%) versus 12/54 (22.2%); p=0.23 and 15/52 (28.8%) versus 11/54 (20.4%); p=0.31]. None of the patients developed ovarian hyperstimulation syndrome (OHSS). The incidence of multiple pregnancies in group 1 was 1/17 (5.9%) (p=0.31). Conclusion: The stair-step protocol with letrozole allows repeated stimulation without inducing a menstrual-like response and can be considered an effective treatment of anovulatory infertility in PCOS. It reduces the time to ovulation approximately twofold without increasing the risk of OHSS and multiple pregnancies, thus improving patients' quality of life.

ovulation induction, letrozole, stair-step protocol, polycystic ovary syndrome, infertility