title: Fertilization, embryo development, and clinical outcome of immature oocytes obtained from natural cycle in vitro fertilization.
abstract: OBJECTIVE
  To analyze the fertilization, embryo development, and clinical outcome of immature oocytes obtained from natural cycle IVF in women with regular cycles.
  
  
  METHODS
  Natural cycle IVF was performed in 28 patients who had normal ovaries, > 6 antral follicle counts and were less than 40 years old (n=28 cycles). An hCG trigger of 10,000 IU was administered 36 h before oocyte collection when the diameter of the dominant follicle (DF) was over 12 mm. Oocytes were retrieved from DF as well as from the cohort of smaller follicles. Embryological aspects of the mature and immature oocytes retrieved from these cycles as well as the implantation and clinical pregnancy rates depending on the origin of the embryos transferred were evaluated.
  
  
  RESULTS
  Overall clinical pregnancy and implantation rates were 20.8 % and 6.7 %, respectively. There were no differences in in vitro maturation (IVM), fertilization and embryo development between immature oocytes retrieved with and without in vivo matured oocytes. However, the clinical and implantation rates in cycles with embryos produced from in vivo matured oocytes transferred were better than the cycles where only IVM embryos were transferred (30.8 %, 9.1 % vs. 9.1 %, 3.2 %).
  
  
  CONCLUSIONS
  Although our results show that immature oocytes from natural cycle IVF can fertilize normally and can be used to increase the number of embryos available for transfer, the embryos derived from the immature oocytes in natural cycles IVF have a poorer reproductive potential.
authors.affiliation: MUHC reproductive center, Department of Obstetrics and Gynecology, Royal Victoria Hospital, McGill University, Montreal, Quebec, H3A 1A1, Canada. weon-young.son@muhc.mcgill.ca
authors.forename: Weon-Young
authors.initials: WY
authors.lastname: Son
authors.forename: Jin-Tae
authors.initials: JT
authors.lastname: Chung
authors.forename: Mausumi
authors.initials: M
authors.lastname: Das
authors.forename: William
authors.initials: W
authors.lastname: Buckett
authors.forename: Ezgi
authors.initials: E
authors.lastname: Demirtas
authors.forename: Hananel
authors.initials: H
authors.lastname: Holzer
mesh_terms: D000328:Adult; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D004624:Embryo Transfer / Q000379:methods; D047108:Embryonic Development; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D059471:In Vitro Oocyte Maturation Techniques / Q000379:methods; D050498:Live Birth; D008597:Menstrual Cycle / Q000187:drug effects / Q000502:physiology; D054315:Oocyte Retrieval / Q000379:methods; D009865:Oocytes / Q000254:growth & development*; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D006063:Chorionic Gonadotropin