title: Selection of the optimal day for oocyte retrieval based on the diameter of the dominant follicle in hCG-primed in vitro maturation cycles.
abstract: BACKGROUND
  The efficiency of in vitro maturation (IVM) techniques is suboptimal compared with controlled ovarian stimulation combined with IVF cycles, and studies are needed to identify factors that predispose IVM cycles to success or failure. We compared the outcome of IVM cycles with different dominant follicle (DF) size at oocyte retrieval following hCG priming.
  
  
  METHODS
  IVM was performed in 160 patients with polycystic ovaries (171 cycles). We administered 10,000 IU hCG s.c. 35-38 h before oocyte collection when endometrial thickness reached at least 6 mm. IVM cycles were retrospectively analyzed according to DF diameter as follows; Group 1: DF diameter <or=10 mm, Group 2: between 10 and 14 mm, Group 3: >14 mm. RESULTS A positive correlation was observed between DF size and number of in vivo matured oocytes collected (Group 1, 2 and 3 = 6.9, 10.6 and 15.1%, respectively). The rates of IVM, fertilization and embryo development were similar among the sibling immature oocytes collected from the three groups. However, clinical pregnancy rate in Group 2 (40.3%) was higher than Group 3 (17.1%) (P < 0.05). Moreover, implantation rates in Groups 1 (13.6%) and 2 (14.3%) were higher than Group 3 (4.9%) (P < 0.01).
  
  
  CONCLUSIONS
  Our results suggest that oocyte collection in IVM cycles should be performed when the DF is 14 mm diameter or less. Sibling immature oocytes may be affected detrimentally if a DF >14 mm is present at oocyte collection.
authors.affiliation: Department of Obstetrics and Gynecology, McGill Reproductive Center, Royal Victoria Hospital, McGill University, Montreal, QC, 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: Belen
authors.initials: B
authors.lastname: Herrero
authors.forename: Nicola
authors.initials: N
authors.lastname: Dean
authors.forename: Ezgi
authors.initials: E
authors.lastname: Demirtas
authors.forename: Hananel
authors.initials: H
authors.lastname: Holzer
authors.forename: Shai
authors.initials: S
authors.lastname: Elizur
authors.forename: Ri-Cheng
authors.initials: RC
authors.lastname: Chian
authors.forename: Seang Lin
authors.initials: SL
authors.lastname: Tan
mesh_terms: D006063:Chorionic Gonadotropin / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000209:etiology; D054315:Oocyte Retrieval / Q000379:methods*; D006080:Ovarian Follicle / Q000166:cytology*; D010062:Ovulation Induction / Q000379:methods; D011085:Polycystic Ovary Syndrome / Q000150:complications; D011247:Pregnancy
chemical_list: D006063:Chorionic Gonadotropin