Maternal bleeding complications in pregnancies affected by red blood cell alloimmunization

Abstract

\n Purpose\n\nTo investigate whether women with red blood cell (RBC) alloimmunization are more likely to experience bleeding complications during pregnancy or delivery than women without RBC alloimmunization.\nMethods\n\nRetrospective study involving all singleton pregnancies affected by RBC alloimmunization and without pre-existing maternal bleeding disorders or placenta previa, from 1 July 1999 to 30 June 2019 (“cases”). Only bleedings not related to invasive procedures (amnio- or cordocenteses) were included. Cases were compared to controls without RBC alloimmunization, matched for maternal age and body mass index, from the same tertiary referral center in Austria.\nResults\n\n130 cases were compared to 130 controls. Cases had significantly more previous pregnancies and miscarriages and their newborns had lower birthweight and were more often transferred to the intensive care unit than newborns of controls. 18/130 (13.8%) cases, compared to 8/130 (6.2%) controls experienced any bleeding during pregnancy or delivery (p\u2009=\u20090.061). Bleeding most often happened during the third trimester (cases: 4.6% vs. controls 0.8%, p\u2009=\u20090.12) and during or after delivery (cases: 7.7% vs. controls: 4.6%, p\u2009=\u20090.168). Binary logistic regression for the prediction of any bleeding complication during pregnancy, delivery or postpartum revealed immunization against RBC antigens as the only independent contributor (p\u2009=\u20090.04). Age, smoking, or previous obstetric history had no influence on the likelihood of maternal bleeding complications. Neither RBC antibody specificity nor titers were predictive of maternal bleeding during pregnancy or delivery.\nConclusion\n\nPregnancies affected by RBC alloimmunization are at increased risk of maternal bleeding complications during pregnancy and delivery.