(HealthDay News) — For infertile women with polycystic ovary syndrome, the aromatase inhibitor letrozole is associated with higher live-birth and ovulation rates than clomiphene, according to a study published in the July 10 issue of the New England Journal of Medicine.

Richard S. Legro, MD, from Pennsylvania State University in Hershey, and colleagues conducted a double-blind, multicenter study involving 750 women (age 18–40 years) with polycystic ovary syndrome. Participants were randomized to receive letrozole or clomiphene, in a 1:1 ratio, for up to five treatment cycles.

The researchers found that there were more cumulative live births in the letrozole group than the clomiphene group (27.5 vs. 19.1%; P=0.007; rate ratio for live birth, 1.44). There were four major congenital anomalies in the letrozole group and one in the clomiphene group, but the difference was not significant (P=0.65). There was a higher cumulative ovulation rate with letrozole than clomiphene (61.7 vs. 48.3%; P<0.001). No significant between-group differences were seen in pregnancy loss (31.8 and 29.1%, respectively) or twin pregnancy (3.4 and 7.4%, respectively). The incidence of hot flushes was higher with clomiphene, and fatigue and dizziness higher with letrozole.

“As compared with clomiphene, letrozole was associated with higher live-birth and ovulation rates among infertile women with the polycystic ovary syndrome,” the authors write.

Several authors disclosed financial ties to the pharmaceutical industry.

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