title: Chorionic villus sampling for fetal Rh typing: clinical implications.
abstract: OBJECTIVE
  The prenatal Rh typing of red blood cells obtained by chorionic villus sampling was performed with an immune rosette technique.
  
  
  METHODS
  Ten Rh-negative pregnant women undergoing chorionic villus sampling at 9 to 11 weeks' gestation were studied at a large referral hospital.
  
  
  RESULTS
  Accurate Rh phenotyping may be done on red blood cells obtained from chorionic villi weighing 2 to 8 mg. The preparations were shown to be greater than 90% fetal in origin as demonstrated by radial immunodiffusion quantitation of fetal hemoglobin-containing cells. Of the 10 fetuses typed in the first trimester nine of the pregnancies were carried to term. In all cases typing of red blood cells confirmed the antenatal fetal red cell typing.
  
  
  CONCLUSIONS
  This study shows that antenatal Rh phenotyping may be performed as early as 9 to 11 weeks' gestation. This technique may be used in the management of pregnancies complicated by Rh incompatibility.
authors.affiliation: Department of Laboratory Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: T S
authors.initials: TS
authors.lastname: Kickler
authors.forename: K
authors.initials: K
authors.lastname: Blakemore
authors.forename: R S
authors.initials: RS
authors.lastname: Shirey
authors.forename: S
authors.initials: S
authors.lastname: Nicol
authors.forename: N
authors.initials: N
authors.lastname: Callan
authors.forename: P M
authors.initials: PM
authors.lastname: Ness
authors.forename: C
authors.initials: C
authors.lastname: Escallon
authors.forename: G
authors.initials: G
authors.lastname: Dover
mesh_terms: D001788:Blood Grouping and Crossmatching / Q000379:methods*; D002824:Chorionic Villi / Q000276:immunology*; D004912:Erythrocytes / Q000276:immunology*; D005312:Fetal Blood / Q000166:cytology; D005319:Fetal Hemoglobin / Q000032:analysis; D005333:Fetus / Q000276:immunology*; D006801:Humans; D007163:Immunosorbent Techniques; D010641:Phenotype; D012397:Rosette Formation
chemical_list: D005319:Fetal Hemoglobin