Prenatal Serological Diagnosis of Intrauterine Cytomegalovirus Infection

The document detailed a case where prenatal serological diagnosis of intrauterine cytomegalovirus (CMV) infection was achieved in a 28-year-old pregnant woman. Ultrasonography at 25 weeks' gestation revealed a hydropic fetus, and subsequent tests on fetal serum and ascitic fluid indicated severe erythroblastosis and hypoalbuminaemia. The infant was born prematurely at 27 weeks and did not survive. Initial maternal serology showed an antibody titre of 32 against CMV, but no CMV-specific IgM was found in the fetal serum using indirect immunofluorescence. However, a radioimmunoassay detected a high titre of 4000 for CMV-specific IgM in the fetal serum, confirming intrauterine infection. Additionally, the mother's serum had a CMV-specific IgM titre of 800 at 21 weeks' gestation, suggesting an early primary infection during pregnancy. This case was the first to demonstrate virus-specific IgM in fetal serum obtained in utero, highlighting the utility of radioimmunoassay in diagnosing congenital CMV.