VP46.15: The independent association of preterm delivery with intrapartum and early postpartum bleeding in otherwise uncomplicated singleton pregnancies

The primary aim was to investigate whether preterm delivery was an independent risk factor for blood or blood products transfusion in the intrapartum or postpartum period, considered as a proxy for severe obstetric bleeding. Throughout a nine-month-period, 216 uncomplicated singleton deliveries were included in a cross-sectional design following exclusion of severe maternal and fetal morbidity such as chorioamnionitis, and use of medications including tocolytics. Maternal and neonatal data were evaluated and compared across preterm (between 24 0/7–36 6/7 weeks of gestation) and term (between 37 0/7–41 6/7 weeks of gestation) deliveries. Primary and secondary outcomes were requirement for blood or blood products transfusion until discharge and change in hemoglobin value and hematocrit from baseline to postpartum hour 6, respectively. Logistic regression models were constructed to evaluate the effect of preterm delivery on the primary outcome. There were 90 (41.7%) preterm deliveries with an overall Caesarean section rate of 77.8%. Preterm delivery was not an independent risk factor for the primary outcome, when route of delivery, maternal body-mass index, antenatal steroid administration, and baseline admission platelet and leukocyte counts were controlled for (adjusted risk ratio, 2.46; 95% confidence interval, 0.69-8.77; p = 0.16). Subgroup analysis including Caesarean deliveries revealed similar result (adjusted risk ratio, 1.65; 95% confidence interval, 0.42-6.48; p = 0.47). Secondary outcomes including decrease in mean or percent values of hemoglobin and hematocrit measurements were also similar across preterm and term groups, both after vaginal and Caesarean deliveries (for all comparisons, p > 0.05). Preterm delivery is not independently associated with increased requirement for blood transfusions or decreased hemoglobin and hematocrit values following otherwise uncomplicated vaginal or Caesarean delivery of singletons.