title: Early pregnancy losses in in vitro fertilization and oocyte donation.
abstract: OBJECTIVE
  To evaluate prospectively the incidence of early pregnancy losses (before menstruation occurs) in IVF and ovum donation cycles.
  
  
  METHODS
  Prospective case-control study.
  
  
  METHODS
  Tertiary care, university-associated center.
  
  
  METHODS
  One hundred forty-five patients undergoing IVF and 92 undergoing oocyte donation were recruited. The control group for IVF consisted of 15 ovum donors who had no ET and were instructed to avoid intercourse. The control group for oocyte donation included 10 women undergoing a mock cycle of steroid replacement.
  
  
  METHODS
  Starting on day 6 after ET, the women were instructed to collect the first urine sample of the day every 2 days. Each patient collected six different specimens of urine (days 6, 8, 10, 12, 14, and 16 after ET for cases or the same days without ET for controls.
  
  
  METHODS
  beta-HCG was measured with a standardized microparticle enzyme immunoassay, and IVF reproductive outcome was assessed.
  
  
  RESULTS
  For IVF, positive implantation was registered in 88 of 145 cycles of embryo replacement (60.7%). Only 30 (20.7%) resulted in viable pregnancies, whereas the remaining 58 miscarried. Forty-two of these miscarriages (72.4%) were early pregnancy losses and 13 (22.4%) were classified as clinical abortions. In ovum donation, positive implantation was recorded in 64 of 92 cycles of ET (69.6%). A total of 30 (32.6%) ended in viable pregnancies, whereas the remaining 34 (37.0%) were miscarriages. Early pregnancy loss accounted for 70.6% of pregnancy losses, whereas biochemical pregnancies and clinical abortions accounted for 11.8% and 17.6%, respectively.
  
  
  CONCLUSIONS
  Our results demonstrate that patients undergoing assisted reproductive technology have an increased rate of early pregnancy loss compared with fertile patients. In addition, these data indicate that implantation is more frequently impaired in IVF than in oocyte donation cycles, resulting in a high incidence of early pregnancy loss. This suggests that implantation may be subjected to abnormal conditions in assisted reproduction.
authors.affiliation: Department of Pediatrics, Obstetrics and Gynecology, Valencia University, Spain. csimon@interbook.net
authors.forename: C
authors.initials: C
authors.lastname: Simón
authors.forename: J
authors.initials: J
authors.lastname: Landeras
authors.forename: J L
authors.initials: JL
authors.lastname: Zuzuarregui
authors.forename: J C
authors.initials: JC
authors.lastname: Martín
authors.forename: J
authors.initials: J
authors.lastname: Remohí
authors.forename: A
authors.initials: A
authors.lastname: Pellicer
mesh_terms: D016022:Case-Control Studies; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000652:urine; D010064:Embryo Implantation; D020964:Embryo Loss; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D018587:Oocyte Donation; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D016896:Treatment Outcome
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human