Is parvovirus B19 infection upsurge in 2023–2024 associated with adverse pregnancy outcome?

Objective: A surge in parvovirus B19 infections has been reported in 2023-2024 across Europe and the USA, raising concerns about the associated perinatal risks. The aim of this study was to compare perinatal outcomes following maternal parvovirus B19 infection during the 2023-2024 period with those from a pre-2023 cohort. Methods: This multicenter, retrospective cohort study compared perinatal outcomes in women with maternal parvovirus B19 infection according to whether infection occurred pre-2023 (2012-2022) or between 2023 and 2024. Pregnant women with confirmed parvovirus B19 infection were eligible for inclusion. Cases were excluded if they had incomplete records, an ongoing pregnancy, coinfection with cytomegalovirus or Epstein-Barr virus, pre-existing structural or genetic abnormality, immune fetal hydrops or a maternal serology result not indicative of parvovirus B19 infection. The primary outcome was perinatal mortality, which was defined as intrauterine fetal death >= 20 weeks' gestation or neonatal death <= 28 days after delivery. The secondary outcomes were persistent fetal anemia requiring more than one intrauterine transfusion (IUT) and a composite adverse perinatal outcome (CAPO), defined as the presence of one or more adverse outcomes, including perinatal mortality, pregnancy loss < 20 weeks, new-onset structural anomaly and termination of pregnancy owing to parvovirus-related morbidity. Differences between the two groups were assessed using standard statistical tests, and a generalized linear mixed model was used to identify predictors of perinatal mortality in the 2023-2024 cohort. Results: Following exclusions, 140 cases from pre-2023 and 175 cases from 2023-2024 were analyzed. The rate of fetal hydrops at presentation was similar across the two groups (22.9% in pre-2023 vs 23.4% in 2023-2024; P = 0.905). The rates of perinatal mortality (6.4% in pre-2023 vs 8.0% in 2023-2024; P = 0.294) and CAPO (17.9% in pre-2023 vs 21.7% in 2023-2024; P = 0.395) were not significantly different between groups, but the proportion of fetuses with persistent fetal anemia requiring a second IUT was significantly higher in the 2023-2024 cohort (46.0% vs 19.4%; P = 0.011). For the 2023-2024 cohort, fetal hydrops at presentation was an independent predictor of perinatal mortality (adjusted odds ratio, 10.91 (95% CI, 1.89-63.07); P = 0.007). Conclusion: In this multicenter collaboration, we report perinatal outcomes following maternal parvovirus B19 infection during the recent upsurge and compare them with those of a historical cohort. Although perinatal mortality and CAPO rates were similar between cohorts, cases in the recent surge (2023-2024) required more prenatal interventions, including the need for more than one IUT. Early identification and monitoring remain essential to mitigate adverse perinatal outcomes following maternal parvovirus B19 infection. (c) 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.