[Ultrasound in the evaluation of intrauterine infection during pregnancy]

Ultrasound has an important role in the detection and follow- up of intrauterine infection. Viral infections are a major cause of fetal morbidity and mortality. Transplacental transmission of the virus, even in sub-clinical maternal infection, may result in a severe congenital syndrome. Prenatal detection of viral infection is based on fetal sonographic findings and PCR to identify the specific infectious agent. Most affected fetuses appear sonographically normal, but serial scanning may reveal evolving findings. Common sonographic abnormalities, although non-specific, may be indicative of fetal viral infections. These include growth restriction, ascites, hydrops, ventriculomegaly, intracranial calcifications, hydrocephaly, microcephaly, cardiac anomalies, hepatosplenomegaly, echogenic bowel, placentomegaly and abnormal amniotic fluid volume. Some of the pathognomonic sonographic findings enable diagnosis of a specific congenital syndrome (e.g., ventriculomegaly and intracranial and hepatic calcifications in cytomegalovirus or in toxoplasma; eye and cardiac anomalies in congenital Rubella syndrome; limb contractures and cerebral anomalies in Varicella Zoster virus). When abnormalities are detected on ultrasound, a thorough fetal evaluation is recommended because of multiorgan involvement.