Predictive Value of Elevated LH/FSH Ratio for Ovulation Induction in Patients with Polycystic Ovary Syndrome

To assess the value of an elevated luteinizing hormone (LH)-to-follicle-stimulating hormone (FSH) ratio in predicting development of a dominant follicle when ovulation induction is implemented with clomiphene citrate (CC) or letrozole in women with polycystic ovary syndrome (PCOS).

Retrospective review of 312 monitored cycles between 2007 and 2012. All patients met the diagnostic criteria set by the 2006 Androgen Excess-PCOS Society and had baseline LH and FSH levels drawn. Only ovulation induction with CC or letrozole was included. Primary outcome was development of a dominant follicle of ≥ 18 mm.

The development of a dominant follicle was significantly associated with clinical pregnancy. The development of a dominant follicle was also higher in the letrozole group as compared to the CC group (87.6% [155/177] vs. 62.2% [84/135], p < 0.001). Furthermore, treatment with letrozole significantly increased the odds of forming a dominant follicle when LH/FSH ratio was ≥ 1 (odds ratio [OR] 7.69, CI 3.69-16.02). When LH/ FSH ratio was < 1, letrozole had no significant effect on dominant follicle development (OR of 3.63, CI 0.92-14.25).

LH/FSH ratio ≥ 1 could be useful as a predictive tool to identify which subgroup of PCOS patients may be more successful in forming a dominant follicle when using letrozole as compared to CC.