Médecine de la Reproduction


Letrozole or Clomiphene citrate to treat anovulatory PCOS Volume 26, issue 1, janvier-février-mars 2024



Centre de PMA, clinique Mont-Légia, Liège, Belgique
* Tirés à part : A. Delvigne

The update of guidelines for the pharmacological management of anovulation of PCOS leads us towards a new type of inhibition of the negative feedback of E2 on the hypothalamo-pituitary axis. Blocking E2 receptors via a selective estrogen receptor modulator is advantageously replaced by lowering the serum concentration of E2 through aromatase inhibition. The lack of effect on peripheral E2 receptors, especially at the endometrial level, is likely the reason for the superiority of Letrozole over Clomiphene citrate in terms of ovulation rate and live births rate, with a very high level of evidence and certainty. The pharmacology of Letrozole, with its short half-life, along with 46 randomized and cohort studies, reassures us regarding its lack of teratogenicity. The therapeutic advantages of Letrozole and the absence of evidence of harm to the fetus make it a first-line agent for ovulation induction in PCOS patients or in cases of resistance to Clomiphene Citrate.