Fetal Anemia: Determinants and Perinatal Outcomes according to the Method of Intrauterine Blood Transfusion.

INTRODUCTION: Fetal anemia from hemolytic disease treated by intrauterine transfusion (IUT) can be performed by intraperitoneal, intracardiac, and intravascular transfusion (IVT). Objective of our study was to compare different transfusion techniques. METHODS: Retrospective review of IUT secondary to red cell alloimmunization was conducted at eight international centers from 2012 to 2020. Severe anemia suspected if middle cerebral artery peaks systolic velocity ≥1.5 multiples of the median. Demographic, delivery, and postnatal variables were analyzed. RESULTS: Total of 344 procedures, 325 IVT and 19 other techniques (non-IVT) included. No difference in demographics, history of stillbirth (20.5 vs. 15.8%, p = 0.7), prior pregnancy IUT (25.6 vs. 31.6%, p = 0.5) or neonatal transfusion (36.1 vs. 43.8%, p = 0.5). At first IUT, non-IVT had higher hydrops (42.1% vs. 20.4%, p = 0.03), lower starting hematocrit (13.3% [±6] vs. 17.7% [±8.2], p = 0.04), and trend toward lower gestational age (24.6 [20.1-27] vs. 26.4 [23.2-29.6] weeks, p = 0.08). No difference in birthweight, neonatal phototherapy, exchange, or simple transfusion was observed. CONCLUSION: This is one of the largest studies comparing techniques to treat fetal anemia. IVT was most performed, other techniques were more likely performed in hydrops, and lower starting hematocrit was seen. Neither technique affected outcomes. This study may suggest that physician's experience may be the strongest contributor of outcomes.

Magnesium sulfate titration reduces maternal complications following fetoscopic closure of spina bifida.

OBJECTIVE: To evaluate if magnesium sulfate (MgSO4 ) titration following fetoscopic spina bifida closure is associated with fewer maternal complications than the Management of Myelomeningocele Study (MOMS) tocolytic regimen. METHODS: This prospective cohort study included 73 consecutive patients undergoing fetoscopic closure of spina bifida between 2015 and 2020. A policy of using the MgSO4 regimen per the MOMS trial was changed to a flexible one in which MgSO4 was titrated according to the frequency of the uterine contractions following surgery. The frequency of maternal pulmonary edema, low maternal oxygen saturation requiring oxygen supplementation, atelectasis, hypocalcemia, and preterm delivery was compared before and after the policy was changed. RESULTS: A higher proportion of women in the group that used the MOMS MgSO4 regimen had pulmonary edema compared to those in the flexible one (26.1% [6/23] vs. 6% [3/50]; p = 0.024). Multivariate analysis showed that the MOMS tocolytic regimen was independently associated with a higher risk of pulmonary edema (adjusted odds ratio: 8.57; 95% confidence interval: 1.54-47.7; p = 0.014) than a flexible one. There was no difference in the rate of preterm delivery. CONCLUSION: Following fetoscopic closure of spina bifida, the MOMS MgSO4 regimen is associated with an increased risk of pulmonary edema than a more flexible regimen.