title: Aromatase inhibitors in stimulated IVF cycles.
abstract: Aromatase inhibitors have been introduced as a new treatment modality that could challenge clomiphene citrate as an ovulation induction regiment in patients with PCOS. Although several randomized trials have been conducted regarding their use as ovulation induction agents, only few trials are available regarding their efficacy in IVF stimulated cycles. Current available evidence support that letrozole may have a promising role in stimulated IVF cycles, either when administered during the follicular phase for ovarian stimulation. Especially for women with poor ovarian response, letrozole appears to have the potential to increase clinical pregnancy rates when combined with gonadotropins, whereas at the same time reduces the total gonadotropin dose required for ovarian stimulation. However, given that in all of the trials letrozole has been administered in GnRH antagonist cycles, it is intriguing to test in the future how it may perform when used in GnRH agonist cycles. Finally administration of letrozole during luteal phase in IVF cycles offers another treatment modality for patients at high risk for OHSS taking into account that it drastically reduces estradiol levels.
authors.affiliation: Human Reproduction and Genetics Foundation, Adrianoupoleos 6, 55133 Thessaloniki, Greece. drvagpapanikolaou@yahoo.gr
authors.forename: Evangelos G
authors.initials: EG
authors.lastname: Papanikolaou
authors.forename: Nikolaos P
authors.initials: NP
authors.lastname: Polyzos
authors.forename: Peter
authors.initials: P
authors.lastname: Humaidan
authors.forename: George
authors.initials: G
authors.lastname: Pados
authors.forename: Ernesto
authors.initials: E
authors.lastname: Bosch
authors.forename: Herman
authors.initials: H
authors.lastname: Tournaye
authors.forename: Basil
authors.initials: B
authors.lastname: Tarlatzis
mesh_terms: D047072:Aromatase Inhibitors / Q000627:therapeutic use*; D002996:Clomiphene / Q000627:therapeutic use; D005260:Female; D005307:Fertilization in Vitro; D005498:Follicular Phase / Q000187:drug effects; D006062:Gonadotropins / Q000627:therapeutic use; D006801:Humans; D000077289:Letrozole; D008183:Luteal Phase / Q000187:drug effects; D009570:Nitriles / Q000627:therapeutic use*; D010062:Ovulation Induction / Q000379:methods*; D011247:Pregnancy; D018873:Pregnancy Rate; D014230:Triazoles / Q000627:therapeutic use*
chemical_list: D047072:Aromatase Inhibitors; D006062:Gonadotropins; D009570:Nitriles; D014230:Triazoles; D002996:Clomiphene; D000077289:Letrozole