To examine the incidence and significance of complications related to percutaneous fetal blood sampling, we reviewed all the articles published in the English literature on this procedure. Risks of complications and adverse outcomes depend mainly on the gestational age at the time of the procedure, the operator's experience, and the indication for the procedure. To determine the incidence of fetal losses, we pooled the data from series with > 100 cases. After exclusion of cases where some fetal pathologic condition was present, we determined the incidence of adverse outcomes in a low-risk population. In this population fetal blood sampling performed by an experienced operator carries about a 1.4% risk of fetal loss before 28 weeks' gestation and a 1.4% risk of perinatal death (after 28 weeks).