Maternal-fetal alloimmunization: perinatal outcomes in a reference hospital in Northeastern Brazil

To assess the prevalence of maternal alloantibodies in pregnant women at a maternity hospital in northeastern Brazil and describe their perinatal outcomes.

A retrospective cohort study reviewed maternal and newborn medical records between January 2017 and October 2018 to assess for the presence of maternal alloantibodies.

The following maternal alloantibodies were found in the 41 cases surveyed: anti-D, 28 cases (45%); anti-C, 7 cases (11%); anti-c, 1 case (1.6%); anti-E, 4 cases (6.4%); anti-Cw, 1 case (1.6%); anti-K, 2 cases (3.2%); anti-Jka, 1 case (1.6%); anti-M, 3 cases (4.8%); anti-Fya, 2 cases (3.2%); anti-Fyb, 1 case (1.6%); anti-Lea, 5 cases (8%); anti-Leb, 3 cases (4.8%); and anti-Dia, 4 cases (6.4%). Anti-D antibodies were the most frequent cause of erythrocyte alloimmunization (80%). Fetal anemia was observed in four pregnancies based on the peak systolic velocity of the middle cerebral artery. In one case, the mother showed anti-M, and anti-Lea alloimmunization, but the direct antiglobulin test results for the newborn were negative, and no unfavorable neonatal outcomes were observed. In one case of a mother with anti-C and anti-D alloimmunization, the neonate showed anti-D antibodies only in the serological panel and required phototherapy. Neonates with plasma antibodies and jaundice requiring phototherapy only had a serological panel with anti-D, anti-C, anti-c, and anti-E antibodies. Intervention was required for 2.5% of pregnant women with positive antibody screens and 81% of newborns with positive direct antiglobulin test results.

Despite being a rare condition, maternal alloimmunization by irregular antibodies can result in high perinatal morbidity and mortality.