title: A randomized, single-blind, prospective trial comparing three different gonadotropin doses with or without addition of letrozole during ovulation stimulation in patients with poor ovarian response.
abstract: OBJECTIVE
  The aim of this randomized controlled trial (RCT) was to investigate whether IVF outcomes would differ between patients with POR who received three different gonadotropin doses with or without the addition of letrozole during ovulation stimulation.
  
  
  METHODS
  Only those who fulfilled two of the three Bologna criteria were included to the study. 95 patients met the inclusion criteria and agreed to participate in the study. In the first group, 31 patients were treated with 450IU gonadotropins. In the second group, 31 patients were treated with 300IU gonadotropins. The third group comprised 33 patients and was treated with 150IU gonadotropins in combination with letrozole.
  
  
  RESULTS
  The results indicate that differences in doses of hMG and rFSH in patients with POR result in a similar number of retrieved MII and fertilized oocytes, similar fertilization rates, number of transferred embryos, implantation, cancelation, chemical, clinical, and ongoing pregnancy rates.
  
  
  CONCLUSIONS
  Increasing the dose of gonadotropins during ovulation stimulation is an intuitively appealing approach when the patient is a poor responder. However, increasing the dose does not necessarily improve the reproductive outcome. Using a mild stimulation with addition of letrozole was as effective as stimulation with higher doses of gonadotropins alone in this patient population.
authors.affiliation: Department of Obstetrics and Gynecology, Istanbul University School of Medicine, Istanbul, Turkey. Electronic address: ercan.bastu@istanbul.edu.tr.
authors.forename: Ercan
authors.initials: E
authors.lastname: Bastu
authors.affiliation: Department of Obstetrics and Gynecology, Istanbul University School of Medicine, Istanbul, Turkey.
authors.forename: Faruk
authors.initials: F
authors.lastname: Buyru
authors.affiliation: Department of Obstetrics and Gynecology, Istanbul University School of Medicine, Istanbul, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Ozsurmeli
authors.affiliation: Department of Obstetrics and Gynecology, Istanbul University School of Medicine, Istanbul, Turkey.
authors.forename: Irem
authors.initials: I
authors.lastname: Demiral
authors.affiliation: Department of Obstetrics and Gynecology, Istanbul University School of Medicine, Istanbul, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Dogan
authors.affiliation: Department of Obstetrics and Gynecology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: John
authors.initials: J
authors.lastname: Yeh
mesh_terms: D000293:Adolescent; D000328:Adult; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D004624:Embryo Transfer; D005260:Female; D005300:Fertility Agents, Female / Q000008:administration & dosage / Q000627:therapeutic use*; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage / Q000627:therapeutic use*; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D006801:Humans; D007247:Infertility, Female / Q000188:drug therapy / Q000628:therapy*; D000077289:Letrozole; D008596:Menotropins / Q000008:administration & dosage / Q000627:therapeutic use*; D009570:Nitriles / Q000008:administration & dosage / Q000627:therapeutic use*; D010062:Ovulation Induction / Q000379:methods*; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D016037:Single-Blind Method; D016896:Treatment Outcome; D014230:Triazoles / Q000008:administration & dosage / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D005300:Fertility Agents, Female; D009570:Nitriles; D014230:Triazoles; D007987:Gonadotropin-Releasing Hormone; D008596:Menotropins; D000077289:Letrozole; D005640:Follicle Stimulating Hormone; C062876:cetrorelix
keywords: Gonadotropins; Letrozole; Ovulation stimulation; Poor ovarian response