Routine antenatal screening and prenatal diagnosis of vertically transmissible infection

1: Infections in pregnant women

Some infections are more serious in pregnant than non-pregnant women because of the potential for vertical transmission to the fetus or infant (eg, varicella, rubella, cytomegalovirus infection, toxoplasmosis and listeriosis). Pre-pregnancy or routine antenatal screening for presence of, or susceptibility to, some of these infections and appropriate management can prevent adverse fetal or perinatal outcomes; screening should include rubella IgG, hepatitis B surface antigen, serological tests for syphilis and HIV antibody. If certain other vertically transmissible infections are suspected because of a positive antenatal test result, confirmatory tests for maternal and, if indicated, fetal infection are essential before intervention is considered (eg, cytomegalovirus infection). For some vertically transmissible infections that are not readily preventable, appropriate management of maternal infection can reduce fetal damage (eg, toxoplasmosis).

Infectious diseases

Routine antenatal screening can detect some potentially serious infectious diseases or susceptibility to infection and allow intervention to prevent adverse outcomes. However, screening programmes can only be justified if appropriate criteria are met for the quality of laboratory tests and interventions. For many infections that are associated with adverse maternal or fetal effects, there are no suitable, cost-effective methods of screening or prevention. However, early diagnosis of infection in high-risk women or those with symptoms can allow preventive intervention. Acute febrile illness or other symptoms consistent with infection during pregnancy should be investigated more diligently than in a non-pregnant woman. Early diagnosis of an apparently trivial maternal infection may prevent serious fetal disease. When the diagnosis of maternal infection is made, appropriate action depends on the nature of infection and the stage of pregnancy at which it occurs. The results of serological test should be confirmed, preferably by a reference laboratory, by retesting the original specimen(s) and/or testing further specimens, as appropriate. Management decisions generally should be made in consultation with an infectious disease physician or clinical microbiologist with experience of infectious diseases in pregnancy.