Fetal circulatory responses to maternal blood loss

We examined the fetal circulatory responses to maternal blood loss in pregn ant women during the third trimester, Seven healthy women with placenta pre via and single-ton pregnancies underwent phlebotomies in an autologous dona tion program. Four hundred milliliters of blood was collected within 15 min at 34 and 35 weeks of gestation. Continuous electric recordings of fetal h eart rate were performed during the first blood collection, and the materna l uterine artery (UtA), umbilical artery (UmA) and fetal middle cerebral ar tery (MCA) Doppler velocity waveforms were recorded before, immediately aft er and 24 h after the second collection in each patient. The average fetal heart rate, maternal UtA and UmA pulsatility indices did not change measura bly during or after maternal blood collections. However, the average fetal MCA pulsatility index decreased significantly 24 h after maternal blood los s. The observation of a decrease in fetal MCA pulsatility index may indicat e delayed fetal asphyxia following mild maternal hemorrhage, Copyright (C) 2001 S.Karger AG, Basel.