PLACENTAL TRANSFUSION-RATE AND UTERINE CONTRACTION

Blood-volume was determined in three hundred and one healthy full-term infants after their cords were clamped at different time-intervals after birth. The infants were divided into two groups, depending on whether the mothers received intravenous methylergometrine during the early third stage of labour or not. The results demonstrated that postnatal transfer of the placental blood to the baby took place at a rapid rate and in a stepwise manner, amounting to about 55% of the baby's blood-volume at birth. This stepwise and rapid rate of placental transfusion correlated with the time of uterine contraction during the third stage of labour. In relation to the uterine contraction at birth, about 23-30% of the blood was transferred during the first 10 to 15 seconds. The remaining 70-77% of blood transfer in the non-methylergometrine group was effected partly at 1 minute and completely at 3 minutes after a uterine contraction, whereas in the methylergometrine group, placental transfusion was accelerated, and the remaining 70-77% of blood was almost completely transferred at 1 minute owing to an earlier and enhanced uterine contraction which, it is suggested, plays a key part. No direct significant influence of respiration on placental transfusion was demonstrated.