title: Preimplantation genetic diagnosis for Down syndrome pregnancy.
abstract: OBJECTIVE
  To evaluate the effect of preimplantation genetic diagnosis (PGD) conducted for women who had Down syndrome pregnancy previously.
  
  
  METHODS
  Trisomy 21 was diagnosed by using fluorescence in site hybridization (FISH) before embryo transfer in two women who had Down syndrome pregnancies. Each received one or two PGD cycles respectively.
  
  
  RESULTS
  Case 1: one PGD cycle was conducted, two oocytes were fertilized and biopsied. One embryo is of trisomy 21 and the other of monosomy 21. No embryo was transferred. Case 2: two PGD cycles were conducted, in total, sixteen oocytes were fertilized and biopsied. Four embryos were tested to be normal, six of trisomy 21, and one of monosomy 21. Five had no signal. Four normal embryos were transferred but no pregnancy resulted.
  
  
  CONCLUSIONS
  For couples who had pregnancies with Down syndrome previously, PGD can be considered, and has been shown to be an effective strategy.
authors.affiliation: Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Chen-ming
authors.initials: CM
authors.lastname: Xu
authors.forename: Yi-min
authors.initials: YM
authors.lastname: Zhu
authors.forename: Min-yue
authors.initials: MY
authors.lastname: Dong
authors.forename: Yu-li
authors.initials: YL
authors.lastname: Qian
authors.forename: Fan
authors.initials: F
authors.lastname: Jin
authors.forename: He-feng
authors.initials: HF
authors.lastname: Huang
mesh_terms: D000328:Adult; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D009006:Monosomy; D011247:Pregnancy; D019836:Preimplantation Diagnosis