title: A prospective, randomized, double-blinded study of assisted hatching in women younger than 38 years undergoing in vitro fertilization.
abstract: OBJECTIVE
  To determine whether assisted hatching is beneficial to IVF patients younger than 38 years whose embryos have a thickened zona pellucida (ZP).
  
  
  METHODS
  Prospective, randomized, double-blinded, crossover study.
  
  
  METHODS
  University-based infertility center.
  
  
  METHODS
  One hundred twenty-one women less than 38 years of age, undergoing IVF at Washington University between April 2004 and February 2007, with ZP thickness > or =13 microm for any embryos.
  
  
  METHODS
  Measurement of ZP thickness in embryos undergoing IVF; randomization of women with embryos with ZP thickness > or =13 microm to no procedure or assisted hatching performed by acidic Tyrode's solution.
  
  
  METHODS
  Clinical intrauterine pregnancy rate, implantation rate, spontaneous pregnancy loss, and live birth rate.
  
  
  RESULTS
  Baseline characteristics and ZP thickness were not significantly different between the two study arms (hatched and unhatched). No significant differences were observed between hatched and unhatched patients in the rates of clinical pregnancy (47% vs. 50% respectively) or live birth (46% vs. 45% respectively). Further, no significant differences were noted between hatched and unhatched groups in rates of spontaneous abortions, monozygotic twinning, dizygotic twinning, chromosomal abnormalities, or ectopic gestations. In addition, mean ZP thickness did not have a significant effect on pregnancy.
  
  
  CONCLUSIONS
  In patients younger than 38 years with embryos with ZP thickness of > or =13 microm, assisted hatching does not improve the rates of implantation, clinical pregnancy, or live birth, and thus does not appear to offer any benefit to patients in this age group undergoing IVF.
authors.affiliation: Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri 63108, USA.
authors.forename: Andrea R
authors.initials: AR
authors.lastname: Hagemann
authors.forename: Susan E
authors.initials: SE
authors.lastname: Lanzendorf
authors.forename: Emily S
authors.initials: ES
authors.lastname: Jungheim
authors.forename: Aimee S
authors.initials: AS
authors.lastname: Chang
authors.forename: Valerie S
authors.initials: VS
authors.lastname: Ratts
authors.forename: Randall R
authors.initials: RR
authors.lastname: Odem
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology; D000328:Adult; D004311:Double-Blind Method; D010064:Embryo Implantation / Q000502:physiology; D004624:Embryo Transfer / Q000379:methods; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D007247:Infertility, Female / Q000209:etiology / Q000503:physiopathology; D050498:Live Birth; D018579:Patient Selection; D011247:Pregnancy; D018873:Pregnancy Rate; D011897:Random Allocation; D027724:Reproductive Techniques, Assisted; D015044:Zona Pellucida / Q000473:pathology