Objectives: To compare the adverse pregnancy outcomes among the three groups of umbilical cord bleeding following cordocentesis; a group of no bleeding (group 1), transient bleeding (group 2), and persistent bleeding (>60 s: group 3). Methods: Consecutive cases of cordocentesis were prospectively recorded and followed up. The inclusion criteria for analysis consisted of (1) singleton pregnancies; (2) gestational age of 18-22 weeks; (3) no fetal anomalies; (4) no previous invasive procedures; (5) performed by experienced operators, and (6) known pregnancy outcomes. The main outcomes were rates of fetal loss, low birth weight and preterm birth. Results: Of 2,174 procedures, 1,614 were in group 1, 509 were in group 2, and 51 were in group 3. The mean birth weight and gestational age at delivery were significantly lower in group 3 than those in groups 1 and 2. The fetal loss rate was significantly higher in group 3. Rates of low birth weight and preterm birth were significantly higher in group 3 whereas the rates in group 2 had a tendency to be higher than those in group 1. Conclusion: This study suggests that cord bleeding during cordocentesis carries a higher risk of fetal loss, low birth weight and preterm birth. Copyright © 2012 S. Karger AG, Basel.