Women who received letrozole had more cumulative live births than those who received clomiphene ( @ of @ -LSB- @ % -RSB- vs. @ of @ -LSB- @ % -RSB- , P = @ ; rate ratio for live birth , @ ; @ % confidence interval , @ to @ ) without significant differences in overall congenital anomalies , though there were four major congenital anomalies in the letrozole group versus one in the clomiphene group ( P = @ ) .