Supplementary Material for: 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 at eight international centers from 2012-2020. Severe anemia suspected if middle cerebral artery peak systolic velocity  1.5 MoM. 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 towards 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. 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.

引言：由溶血病引发的胎儿贫血可通过宫内输血（intrauterine transfusion, IUT）进行治疗，具体术式包括腹腔内输血、心腔内输血以及血管内输血（intravascular transfusion, IVT）。本研究旨在对比不同输血技术的临床效果。方法：本研究为回顾性分析，纳入2012年至2020年8家国际中心中因红细胞同种免疫接受宫内输血的病例。当胎儿大脑中动脉收缩期峰值流速≥1.5倍中位数（MoM）时，即可怀疑存在重度贫血。本研究对受试者的人口学特征、分娩情况及产后相关变量进行了分析。结果：本研究共纳入344例宫内输血操作，其中325例为血管内输血，19例为其他非血管内输血技术。两组受试者在人口学特征、死胎病史（20.5% vs 15.8%，p=0.7）、既往妊娠宫内输血史（25.6% vs 31.6%，p=0.5）以及新生儿输血率（36.1% vs 43.8%，p=0.5）方面均无显著差异。首次宫内输血时，非血管内输血组的胎儿水肿发生率更高（42.1% vs 20.4%，p=0.03），初始红细胞比容更低[13.3%（±6）vs 17.7%（±8.2），p=0.04]，且妊娠周数有更低的趋势（24.6周[20.1-27] vs 26.4周[23.2-29.6]，p=0.08）。两组在出生体重、新生儿光疗、换血治疗或单纯输血方面均无显著差异。结论：本研究是对比胎儿贫血治疗技术的规模最大的研究之一。血管内输血是最常用的术式，其他输血技术更多应用于存在胎儿水肿且初始红细胞比容较低的病例。两种输血技术均未对妊娠结局产生显著影响。本研究提示，医师的临床经验可能是影响妊娠结局的最关键因素。