Objective: To evaluate the incidence and volume of feto-maternal hemorrhage following cordocentesis.
Study Design: Descriptive study.
Material and Method: One hundred and sixteen asymptomatic non-anemic pregnant women with an indication for cordocentesis at 18-22 weeks of gestation between January and June 2004 were recruited. Maternal
blood samples were obtained immediately before and 30 minutes after cordocentesis. Fetal cells in the maternal blood were counted using Kleihauer Betke test. About 25,000 maternal cells per slide were scanned by the same examiner. Feto-maternal hemorrhage was considered significant if the fetal bleeding was more than 0.25 ml.
Results: There was a significant increase in fetal blood volume in maternal circulation after cordocentesis (Paired Student’s t test, p < 0.001). A significant hemorrhage (>0.25 ml) occurred in 63 from 116 women (54.7%). Only one had marked hemorrhage of more than 5.0 ml and none had massive hemorrhage (> 15 ml).
Conclusion: Cordocentesis at 18-22 weeks of gestation can be associated with feto-maternal hemorrhage in more than half of the cases but nearly all cases had only minimal hemorrhage and none had massive hemorrhage.

Keywords: Cordocentesis, Feto-maternal hemorrhage, Prenatal diagnosis