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Byline: Timothy G. Overton, Antony D. Lighten, Nicholas M. Fisk, Phillip R. Bennett Keywords: Fetal cells; transcervical; polymerase chain reaction; fluorescence in situ hybridization; prenatal diagnosis Abstract: OBJECTIVE: We investigated whether reliable prenatal diagnosis is possible from fetal cells harvested transcervically in first-trimester pregnancies. STUDY DESIGN: Fetal cells were obtained transcervically from 87 women undergoing pregnancy termination. Fetal gender was determined in 51 pregnancies with three different polymerase chain reaction techniques and in 36 pregnancies with fluorescent in situ hybridization. In known male pregnancies the number of male fetal cells present was also determined. RESULTS: Polymerase chain reaction detected male deoxyribonucleic acid in up to 79% of cases in male pregnancies and up to 45% of cases in female pregnancies. Fetal gender was correctly predicted in up to 72% of cases with fluorescent in situ hybridization. However, fetal cells were identified in Author Affiliation: London, United Kingdom Article History: Received 3 October 1995; Revised 2 November 1995; Accepted 29 January 1996 Article Note: (footnote) [star] From the Royal Postgraduate Medical School, Institute of Obstetrics and Gynaecology, Queen Charlotte's and Chelsea Hospital., [star][star] Supported by grants from Action Research., a Reprint requests: T.G. Overton, MB, BS, Royal Postgraduate Medical School, Institute of Obstetrics and Gynaecology, Queen Charlotte's and Chelsea Hospital, Goldhawk Road, London, United Kingdom W6 OXG., aa 0002-9378/96 $5.00 + 0 6/1/72364

The RhD blood type of fetuses may be determined early in pregnancy through the analysis of amniotic fluid without sensitizing the mothers' blood to the fetus's different blood type. Such analysis may enable doctors to know whether or not to treat the mother with anti-D immunoglobulin to prevent sensitization of the mother's blood and poor outcomes for the fetus. Researchers performed amniocentesis on 95 pregnant women whose blood was RhD negative and where the father's blood was RhD positive. Amniotic fluid was analyzed for fetal RhD type by polymerase chain reaction and the results were compared to either fetal blood samples or to samples of umbilical cord blood after birth. Thirty-six fetuses were correctly typed as RhD negative, and 96 of 98 fetuses were correctly typed as RhD positive.