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

Objective: To assess the prevalence of maternal alloantibodies in pregnant women at a maternity hospital in northeastern Brazil and describe their perinatal outcomes.
Methods: A retrospective cohort study reviewed maternal and newborn medical records between January 2017 and October 2018 to assess for the presence of maternal alloantibodies.
Results: 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.
Conclusion: Despite being a rare condition, maternal alloimmunization by irregular antibodies can result in high perinatal morbidity and mortality.