title: Outcomes of preimplantation genetic diagnosis using either zona drilling with acidified Tyrode's solution or partial zona dissection.
abstract: OBJECTIVE
  To review the outcomes of preimplantation genetic diagnosis (PGD) using zona drilling with acid Tyrode's solution (chemical zona pellucida drilling, chemical ZD) and those of partial zona dissection (PZD).
  
  
  METHODS
  Clinical outcomes of seventy-one couples undergoing 85 PGD cycles from January 2005 to December 2010 were included. Blastocyst formation and the hatching rate, clinical pregnancy rate, ongoing pregnancy rate, implantation rate, and fetal gender ratio of the PZD and chemical ZD groups were compared.
  
  
  RESULTS
  Application of PZD resulted in a significantly higher rate of clinical pregnancy (40.7% vs. 15.4%, p=0.022), ongoing pregnancy (35.6% vs. 11.5%, p=0.023), and implantation (18.1% vs. 5.7%, p=0.007) compared with chemical ZD. Among non-transferred embryos, the rate of blastocyst formation on day 5 (49.1% vs. 39.5%, p=0.016) and hatching on day 6 (47.2% vs. 26.5%, p<0.001) were also significantly higher in the PZD group.
  
  
  CONCLUSIONS
  The mechanical zona dissection method showed better outcomes than chemical ZD in terms of the blastocyst development and pregnancy rate. In this study, the fact that chemical ZD was conducted in different period from mechanical method should be considered in interpreting the result.
authors.affiliation: Institute of Fertility and Genetics, Hamchoon Women's Clinic, Seoul, Korea.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Chung Hyon
authors.initials: CH
authors.lastname: Kim
authors.forename: Soo Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Seung Ah
authors.initials: SA
authors.lastname: Choe
authors.forename: Joong Yeup
authors.initials: JY
authors.lastname: Lee
authors.forename: Byung Chul
authors.initials: BC
authors.lastname: Jee
authors.forename: Doyeong
authors.initials: D
authors.lastname: Hwang
authors.forename: Ki Chul
authors.initials: KC
authors.lastname: Kim
keywords: Acid Tyrode's solution; Embryo biopsy; Partial zona dissection; Zona drilling