title: Examination of fetal cells and cell-free fetal DNA in maternal blood for fetal gender determination.
abstract: BACKGROUND
  To assess applicability of noninvasive methods for prenatal sex determination, both intact fetal cells and cell-free DNA from maternal blood were studied.
  
  
  METHODS
  Maternal peripheral blood samples were obtained from 41 women carrying chromosomally normal fetuses and from 3 women with aneuploid fetuses (47,XX,+18; 47,XY,+18 and 47,XY,+21) at 9-22 weeks of gestation. DNA was extracted from the plasma fraction and analyzed by the nested polymerase chain reaction (PCR) using Y chromosome specific primers. After fetal cells were enriched by MACS, fluorescence in situ hybridization (FISH) with chromosome X and Y specific probes was performed to detect XY cells.
  
  
  RESULTS
  Although Y-chromosome-specific DNA was detected by PCR analysis in all maternal plasma samples with male fetuses, 26% women bearing female fetuses also gave positive results. By FISH analysis, XY cells were detected in not only 58% of women bearing male fetuses, but also 13% of their counterpoints with female fetuses.
  
  
  CONCLUSIONS
  Our findings suggested that consistent results for fetal gender using PCR or FISH cannot be obtained with intact fetal cells and cell-free DNA present in maternal blood and plasma at 9-22 weeks of gestation, despite their apparent abundant presence.
authors.affiliation: Department of Obstetrics and Gynecology, Nagoya City University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Xiao Xi
authors.initials: XX
authors.lastname: Zhao
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Suzumori
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Ozaki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sato
authors.forename: Kaoru
authors.initials: K
authors.lastname: Suzumori
mesh_terms: D000782:Aneuploidy; D041321:Chromosomes, Human, X; D041322:Chromosomes, Human, Y; D004247:DNA / Q000097:blood*; D005189:False Positive Reactions; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D005865:Gestational Age; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011296:Prenatal Diagnosis; D015203:Reproducibility of Results; D012732:Sex Determination Analysis / Q000379:methods*
chemical_list: D004247:DNA