Fetomaternal bleeding following diagnostic amniocentesis.

The frequency of diagnostic amniocentesis is increasing. Fetal bleeding and trauma have long been recognized to be complications of amniocentesis. For detection of fetomaternal bleeding, efficacy of modified Kleihauer-Betke staining and alpha-fetoprotein elevation in maternal blood was assessed. Preamniocentesis ultrasound scanning was found useful in reducing the incidence of fetomaternal bleeding and bloody taps. Elevation of alpha-fetoprotein was found to be a more sensitive indicator of fetomaternal bleeding than was modified Kleihauer-Betke staining. The use of alpha-fetoprotein to detect fetomaternal bleeding associated with amniocentesis is suggested for the identification of Rh-negative patients requiring anti-D gamma-globulin to prevent sensitization.