[Ultrasound diagnosis of fetal infections: current possibilities and limitations]

Fetal infections, particularly those caused by TORCH agents (toxoplasmosis, other [syphilis, varicella-zoster, parvovirus B19], rubella, cytomegalovirus, herpes), may significantly affect fetal growth and development, resulting in a substantial risk of morbidity and mortality. Since infections are mostly preventable causes of congenital anomalies, early diagnosis relies on serological and molecular testing and fetal ultrasound.

The aim of this study was to assess the prevalence of fetal infections and their detectable ultrasound features.

This retrospective study was conducted at the Department of Obstetrics and Gynecology, University of Szeged, analyzing fetal TORCH infection cases between 2020 and 2024. We assessed the prevalence of infections and the associated developmental abnormalities proven by ultrasound, and compared the results with national and international data.

During the examined period, the prevalence of TORCH infections ranged from 0.00% to 0.14%, compared to international data of 1.2%. In our cohort, fetal T. gondii infections occurred in 0.04-0.08% of cases, parvovirus B19 in 0.053-0.14%, and herpes simplex virus infections in 0.027%. In confirmed cases, central nervous system abnormalities (37.5%) and placental edema (37.5%) were the most common, while other abnormalities - such as fetal anemia, hyperechogenic bowel, nonimmune hydrops fetalis, polyhydramnios, pyelectasis - occurred at a lower rate (12.5%).

In the literature, the reported prevalence rates of fetal infections are 0.3-2.0% for parvovirus B19, ~1% for herpes simplex virus, and <0.03% for congenital T. gondii infection. Internationally accepted TORCH-related fetal malformations include nonimmune hydrops fetalis, central nervous system malformations, cardiovascular anomalies, polyhydramnios, and hepatosplenomegaly. Based on our results and literature, ultrasound is the most reliable noninvasive modality for detecting infection-related fetal malformations, but to determine infectious causes microbiological investigations are necessary.

Our prevalence of infections was significantly lower than reported internationally, while ultrasound findings were consistent with the literature. This confirms the international consensus that ultrasound plays a key role in the diagnosis of fetal infections. Orv Hetil. 2026; 167(39): 1552-1564.