Placental drainage of fetal blood at cesarean delivery and feto-maternal transfusion - A randomized controlled trial

OBJECTIVE: To assess the efficacy of placental drainage of fetal blood at the time of cesarean delivery on the incidence of feto-maternal transfusion. METHODS: This randomized trial includes 86 gravid women who underwent cesarean delivery. Forty-four women were assigned to the placental drainage group and 42 to the no-drainage group. Placental drainage was accomplished by cutting and milking the umbilical cord until no further blood flow occurred. All placentas were spontaneously expelled. The primary outcome variable, as assessed by preoperative and postoperative Kleihauer-Betke tests, was the amount of fetal blood (greater than or equal to 0.5 mL) in the maternal circulation. RESULTS: The group having placental drainage of fetal blood before placental delivery showed a significantly lower incidence (3 of 44, 6.8%) of feto-maternal transfusion (P=.003) as compared with the undrained group (14 of 42, 33%; relative risk 0.20, 95% confidence interval 0.065-0.65; number needed to treat=4). CONCLUSION: Placental drainage of fetal blood before spontaneous placental delivery at the time of cesarean delivery significantly reduces the incidence of feto-maternal transfusion.