title: Use of free fetal DNA in prenatal noninvasive detection of fetal RhD status and fetal gender by molecular analysis of maternal plasma.
abstract: OBJECTIVE
  This study evaluates the use of cell-free fetal DNA in the plasma of RhD-negative women for noninvasive early detection of fetal RhD status and gender.
  
  
  METHODS
  Ninety RhD-negative pregnant women were enrolled in the study. Amplification by real-time polymerase chain reaction (PCR) of RhD gene sequences and SRY gene sequence for the diagnosis of fetal RhD and sex was performed.
  
  
  RESULTS
  Among 90 RhD-negative women, according to phenotypic diagnosis, there were 61 RhD-positive and 29 RhD-negative fetuses. Also, 37 were males and 53 were females. In the first trimester, the sensitivity and the diagnostic accuracy of real-time PCR for Rh genotyping were 93.5% and 91.1%, increasing to 100% and 97.78%, respectively, in the second trimester. With regard to fetal sex determination, in the first trimester, PCR results had a sensitivity of 95.2% and a diagnostic accuracy of 97.8%, both increasing to 100% in the second trimester.
  
  
  CONCLUSIONS
  The use of cell-free fetal DNA in prenatal noninvasive early detection of fetal RhD status and gender by real-time PCR is highly sensitive and accurate as early as the 11th week of gestation for RhD status and the 7th week of gestation for fetal sex.
authors.affiliation: Department of Clinical Pathology, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
authors.forename: Mona
authors.initials: M
authors.lastname: Sedrak
authors.forename: Doaa
authors.initials: D
authors.lastname: Hashad
authors.forename: Hesham
authors.initials: H
authors.lastname: Adel
authors.forename: Amal
authors.initials: A
authors.lastname: Azzam
authors.forename: Nermeen
authors.initials: N
authors.lastname: Elbeltagy
mesh_terms: D000328:Adult; D001774:Blood Chemical Analysis / Q000379:methods; D004247:DNA / Q000032:analysis* / Q000097:blood* / Q000378:metabolism; D005260:Female; D005333:Fetus / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D008297:Male; D025202:Molecular Diagnostic Techniques; D009035:Mothers; D011247:Pregnancy / Q000097:blood / Q000235:genetics; D011261:Pregnancy Trimester, First / Q000097:blood / Q000235:genetics; D011296:Prenatal Diagnosis / Q000379:methods*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D012204:Rh-Hr Blood-Group System / Q000032:analysis / Q000235:genetics*; D012680:Sensitivity and Specificity; D012732:Sex Determination Analysis / Q000379:methods*; D055815:Young Adult
chemical_list: D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen; D004247:DNA