Value of fetoscopy in prenatal diagnosis.

A technique of fetoscopy and fetoscopic blood sampling is described that makes maximum use of ultrasound scanning. A particle size analyser is also an integral part of the procedure. The results are based on 170 fetoscopies, 85 of which were performed for diagnostic reasons. The anterior placenta is rarely a cause of failure and in many instances makes fetal blood sampling easier. Pure fetal blood is obtainable from the umbilical cord insertion in 95% of cases sampled after 18 weeks' gestation. Fetal mortality may be as low as 3% and long-term adverse sequelae have not yet been discovered.