The role of targeted next-generation sequencing and ultrasound in diagnosing fetal cytomegalovirus infection: a case report.

Background: Cytomegalovirus (CMV) infection is a leading cause of congenital infection and neonatal morbidity. Conventional diagnostic methods, such as polymerase chain reaction (PCR) and amniocentesis, remain important in the diagnosis of congenital CMV infection, although each method has its own limitations in clinical practice. Case presentation: A 31-year-old woman, gravida 3 para 1, presented for routine prenatal evaluation. At 18 weeks of gestation, ultrasound revealed echogenic bowel and fetal ascites. Amniocentesis at 19 weeks showed normal chromosomal results, but targeted next-generation sequencing (tNGS) detected CMV DNA with a high viral load, confirming intrauterine infection. Results: Despite counseling regarding poor fetal prognosis, the patient chose to continue the pregnancy under close ultrasound surveillance. Progressive hydrops fetalis was observed at 23 weeks, and the pregnancy was terminated at 24 weeks. Conclusion: This case suggests that combining tNGS with ultrasound may provide complementary diagnostic information in selected cases of suspected fetal infection. In this patient, tNGS supported the identification of CMV in amniotic fluid when conventional genetic testing was unremarkable. However, as this is a single-case report, the broader diagnostic performance and clinical utility of tNGS require further validation in larger studies.