OBJECTIVE: To evaluate the characteristics and outcomes of pregnancies with a prenatally detected fetal or placental tumor with associated fetal anemia that underwent intrauterine transfusion (IUT). METHODS: We searched PubMed, EMBASE, Web of Science, Scopus and Google Scholar databases for studies reporting on singleton pregnancies with a prenatally detected fetal or placental tumor complicated by fetal anemia that underwent IUT, published from inception to October 2024. Only articles written in the English language were considered eligible for inclusion. We excluded multiple gestations, fetuses with concomitant structural anomaly, cases that underwent IUT to treat fetal anemia secondary to intraoperative tumor bleeding and cases that received blood products other than red blood cells. Cases in which the tumor was detected postnatally, cases that underwent termination of pregnancy, studies with incomplete data and systematic reviews were also excluded. The primary outcome was perinatal death, defined as intrauterine fetal demise (IUFD) > 22 weeks' gestation or neonatal death within 28 days after birth. Secondary outcomes included IUFD, neonatal death, preterm labor (PTL), preterm prelabor rupture of membranes (PPROM), placental abruption, and spontaneous or medically indicated live preterm birth (PTB). We performed exploratory subgroup analyses, including differences in tumor size according to the presence or absence of additional non-structural complications, as well as differences in baseline characteristics according to perinatal death status and differences in obstetric and perinatal outcomes according to whether the patient underwent prenatal tumor resection, embolization or ablation in addition to IUT. RESULTS: We included 43 cases in our analysis, including 42 cases from 34 articles identified in the literature search and an additional case managed at our institution. The median hemoglobin level before the initial IUT was 7.0 (interquartile range, 6.0-8.8) g/dL. Most cases (92.5%) had an additional non-structural complication at baseline. Prenatal tumor resection, embolization or ablation was performed as an adjunct to IUT in 40.0% of cases. PTL, PPROM or placental abruption complicated 43.2% of cases. PTB occurred in 81.1% of cases. Perinatal death occurred in 11 (25.6%) cases. We identified a higher likelihood of perinatal death in cases with fetal hydrops (odds ratio (OR), 6.3 (95% CI, 1.1-37.7); P = 0.04) or cardiomegaly (OR, 6.3 (95% CI, 1.1-36.9); P = 0.04), and a lower likelihood of perinatal death was associated with higher fetal hemoglobin after the initial IUT (OR, 0.4 (95% CI, 0.2-0.8), P = 0.01). Perinatal death rates were similar regardless of management strategy (12.5% for IUT as a standalone therapy vs 31.3% for IUT as an adjunct to tumor resection, embolization or ablation; P = 0.1). CONCLUSION: Pregnancies with a prenatally detected fetal or placental tumor, complicated by fetal anemia that underwent IUT, have a high rate of additional non-structural complications. The rate of perinatal death in this population is high, likely due to the severity of the fetal condition at baseline and high rates of obstetric complications and PTB. IUT as a standalone therapy may be reasonable in selected cases. However, ideal candidates for this approach and the best management strategies remain to be determined. © 2026 International Society of Ultrasound in Obstetrics and Gynecology.
Schenone et al. (Sun,) studied this question.