تاثير دير بستن بند ناف بر پلي سايتمي نوزادي

Background and purpose : After decades of discussion and debate, there is little agreement about appropriate time to clamp the umbilical cord after birth. With late cordclamping, neonate receives more placental transfusion that may affect blood hematocrit level. The purpose of this study was to evaluate the effect of early and late cordclamping on neonatal polycythemia at 2h and 18h after birth. Materials and methods : In this double blind, randomized, controlled, clinical trial, 64 healthy term vaginaly born neonates were randomly allocated before delivery to having the umbilical cord clamped either at 30s or 3min after birth. During this period of time, neonates were kept at the level of introitus. Measurments of venous hematocrit level of neonates were performed with microhematocrit method, 2h and 18h after birth. Data were obtained by interview, observation and biophysiologic methods and were analyzed using T student, paired T and Covariance analysis tests with sPsS software. Results : There was no significant difference in mean blood hematocrit level of neonates either at 2h (61±4.9% vs 61.6±4.5%) and 18h after birth (56.9±4.1% vs 56.2±3.9%) between early and late cordclamping groups. This was also the case for neonatal polycythemia (20% vs 23.5%). Residual placental blood volume in late cordclamping group was 39.5% lower than the other group (P<0.001). Estimated blood volume of neonate in late cordclamping group was 7.1% higher than the other group (P<0.001). Conclusion : Late cordclamping does not lead to a significant difference in blood hematocrit level of neonate and neonatal polycythemia. However it leads to a significant decrease in residual placental blood volume and a significant increase in estimated blood volume of neonate. Further trials with delay in cordclamping until cessation of cord pulse or alter the level that newborn is kept is recommended.