A study led by Richard Legro and published in the New England Journal of Medicine compared the medications letrozole and clomiphene to determine which is more effective in women with polycystic ovary syndrome (PCOS) who are trying to conceive.
The most commonly used medication for this group of women is clomiphene citrate (Omifin®); however, its success rate is lower (19%) compared to letrozole (27.5%) after six cycles. The twin pregnancy rate is also higher with clomiphene (6.9%) than with letrozole (3.9%). Furthermore, side effects are less frequent with letrozole than with clomiphene. Importantly, neither of the two medications poses any risk to newborns.