ABO and Rh Blood Group Association with Maternal and Neonatal Outcomes.

Background and Objectives: ABO and Rh blood types are known to have associations with health and disease, but studies on their relationship to pregnancy outcomes have been largely inconclusive. We aimed to examine the associations between ABO and Rh blood groups in pregnant women with maternal-neonatal characteristics and outcomes including hypertensive disorders of pregnancy, gestational diabetes, cesarean section rate, preterm birth, postpartum quantitative blood loss, birth weight, and appearance, pulse, grimace, activity, and respiration scores. Methods: At the time of delivery, 2497 consecutive patients were tested for ABO and Rh blood groups. Only those who delivered singleton infants were included in the analysis (2392 patients, 95.8%). Demographic and clinical data were obtained from the electronic medical record. Associations between blood groups and maternal-neonatal characteristics and outcomes were assessed using logistic regression models. A significance threshold of 0.05 was used for all comparisons. Results: Of the 2392 delivering patients, 46.9% were blood group O, 37.5% were blood group A, 12.2% were blood group B, and 3.4% were blood group AB. In addition, 85.9% were Rh-positive and 14.1% Rh-negative. A total of 2127 (88.9%) women delivered at term. The cesarean section rate was 32.4%, 183 (7.7%) had chronic hypertension, 275 (11.5%) had gestational diabetes, and 396 (16.6%) had a postpartum hemorrhage. The median birth weight was 3330 g (interquartile range 2940-3640). No blood groups were significantly associated with these characteristic and outcome measures. Conclusion: At the time of delivery, no significant associations were identified between ABO and Rh blood groups and maternal-neonatal characteristics and outcomes in this delivery cohort of over 2000 women. [ABSTRACT FROM AUTHOR]