Intrauterine Transfusion for Rhesus Alloimmunization: A Historical Retrospective Cohort from A Single Reference Center in Brazil.

Objective: This study aimed to describe the historical experience of a single reference center in Brazil with intrauterine transfusion (IUT) for Rhesus (Rh) alloimmunization, evaluating the major complications and the perinatal outcomes of this procedure. Methods: This retrospective cohort study evaluated data from medical records of pregnant women between 20 and 34 weeks of gestation whose fetuses underwent IUT by cordocentesis between January 1991 and June 2021. The same experienced examiner performed all procedures. Univariate and multivariate logistic regression was used to assess the effect of fetal hydrops, duration of IUT, post-transfusion cord bleeding time, and bradycardia on death (fetal or neonatal). Results: We analyzed data from 388 IUTs in 169 fetuses of alloimmunized pregnant women with a mean age of 29.3 ± 5.1 years. Death and fetal hydrops were significantly associated at first IUT ( p < 0.001). We had two cases of emergency cesarean section (mean of 0.51% per IUT) and three cases of premature rupture of the ovular membranes (mean of 0.77% per procedure). Thirty-six deaths were recorded, including 14 intrauterine and 22 neonatal. A higher percentage of neonatal deaths was observed in the group with post-transfusion cord bleeding time > 120 s (45.8%). The odds of neonatal death were 17.6 and 12.9 times higher in cases with hydrops and bradycardia than in cases without hydrops and bradycardia, respectively. The odds of death (fetal and neonatal) were 79.9 and 92.3 times higher in cases with hydrops and bradycardia than in cases without hydrops and bradycardia, respectively. Conclusions: The most common complications of IUT for Rh alloimmunization were post-transfusion cord bleeding, fetal bradycardia, premature rupture of ovular membranes, and emergency cesarean section. The IUT complication most associated with death (fetal and neonatal) was bradycardia, and the perinatal outcomes were worse in fetuses with hydrops.