title: Evaluation of low-dose letrozole addition to ovulation induction in IVF.
abstract: OBJECTIVE
  The aim was to investigate the impact of low-dose letrozole usage along with gonadotropin treatment in vitro fertilization (IVF) cycles in comparison to gonadotropin treatment alone.
  
  
  METHODS
  Fifty patients were prospectively included in this randomized study and were divided into two groups. Age, demographic features, causes, and period of infertility were adjusted and matched for both groups. Group 1 included 25 patients who received gonadotropin treatment and letrozole along with gonadotropin-releasing hormone (GnRH) antagonist protocol; group 2 included 25 patients who received gonadotropin treatment along with GnRH antagonist protocol.
  
  
  RESULTS
  Total follicle-stimulating hormone (FSH) and daily FSH doses were lower in group 1, although not statistically significant (p > 0.05). The period of ovulation induction was significantly shorter in group 2. While numbers of retrieved oocytes and transferred embryos were lower in group 1, they were not statistically significant (p > 0.05). Number of clinical pregnancies per embryo transfer, number of clinical pregnancies per cycle, and number of ongoing pregnancies (> 16 gestational weeks) were similar in both groups (p > 0.05).
  
  
  CONCLUSIONS
  Addition of low-dose letrozole to gonadotropin treatment in GnRH antagonist protocols may result in a lower dose of gonadotropin administration. However, routine clinical practice remains questionable due to no evident positive effect on pregnancy rates.
authors.affiliation: Department of Obstetrics and Gynecology, Istanbul University School of Medicine, Istanbul, Turkey.
authors.forename: C
authors.initials: C
authors.lastname: Yasa
authors.forename: E
authors.initials: E
authors.lastname: Bastu
authors.forename: O
authors.initials: O
authors.lastname: Dural
authors.forename: E
authors.initials: E
authors.lastname: Celik
authors.forename: B
authors.initials: B
authors.lastname: Ergun
mesh_terms: D000328:Adult; D047072:Aromatase Inhibitors / Q000008:administration & dosage*; D005260:Female; D005307:Fertilization in Vitro; D006062:Gonadotropins / Q000008:administration & dosage / Q000037:antagonists & inhibitors; D006801:Humans; D000077289:Letrozole; D008297:Male; D009570:Nitriles / Q000008:administration & dosage*; D010062:Ovulation Induction; D011247:Pregnancy; D014230:Triazoles / Q000008:administration & dosage*
chemical_list: D047072:Aromatase Inhibitors; D006062:Gonadotropins; D009570:Nitriles; D014230:Triazoles; D000077289:Letrozole