RESUMO
Procoagulant factor VIII (VIIIC) and procoagulant factor VIII antigen (VIIICAg) were measured in 20 samples of pure fetal blood obtained by fetoscopy at mid-term from non-haemophilic fetuses. VIIIC levels ranged from 25 to 89 U/dl (mean 43.5) and VIIICAg from 11 to 43 U/dl (mean 22.3). Samples from 39 consecutive fetuses at risk of haemophilia A gave results indicating haemophilia in 11, and these pregnancies were terminated at the parents' request. Of the remaining 28, 18 have resulted in normal births, 8 still await delivery, and 2 pregnancies were terminated for non-haematological reasons. The results confirm that pure fetal blood can be aspirated fetoscopically for plasma assays of both VIIIC and VIIICAg. Dual measurement enhances the reliability of predicting or excluding haemophilia A, and makes prenatal diagnosis a dependable option for known or potential carriers seeking this information.
Assuntos
Fator VIII/análise , Hemofilia A/diagnóstico , Antígenos/análise , Fator VIII/imunologia , Feminino , Sangue Fetal , Aconselhamento Genético , Hemofilia A/genética , Humanos , Masculino , Gravidez , Segundo Trimestre da Gravidez , Diagnóstico Pré-Natal , Risco , Diferenciação SexualRESUMO
Fetal blood unmixed with maternal blood or amniotic fluid was obtained by direct-vision fetoscopy in 22 consecutive cases at 15--22 weeks' gestation; the investigation was done either for prenatal diagnosis or before therapeutic abortion. Fetal plasma factors VIIIC and IX averaged 50 I.U./dl (S.D. 12.8) and 12.5 I.U./dl (S.D. 2.4), respectively. Two male fetuses at risk of haemophilia had normal factor VIIIC levels by these criteria, and both pregnancies ended in the birth of a normal boy. Five others gave 3 normal and 2 haemophilic results, which were confirmed in two of the three terminated pregnancies.
