Syndrome infectieux fœtal

Abstract

Prenatal diagnosis of foetal infections has been greatly improved these last years since new molecular biology techniques became available, allowing to establish rapid and reliable diagnosis using polymerase chain reaction on amniotic fluid. In France, toxoplasmosis is the most frequently observed congenital parasitic infection. Any occurrence of maternal seroconversion (ascertained or very suspected) during pregnancy constitutes an indication for early clinical and biological check-up of the newborn. A chemo-prophylactic combination of chloroquine and proguanil (Savarine^®) should be recommended in a pregnant woman going to endemic areas, in order to prevent the risk of congenital malaria and its clinical consequences. The cytomegalovirus (CMV)- induced infection is the most frequent maternal-foetal infection. It constitutes the first cause of neuro-sensorial handicaps acquired during intrauterine life. CMV-induced primary infection in a pregnant woman is therefore a situation with major pathological risk for the foetus. The foetal contamination is principally due to hematogenous trans-placental transmission, inducing viral proliferation in the foetus. The B19 parvovirus is commonly considered responsible for the megalerythema, or fifth disease. Embryo-foetopathies associated to parvovirus infections are now better understood: the rate of maternal-foetal transmission and the risk of complications are better identified. Rubella which is a benignant infection occurring during early childhood was the first infectious disease identified as responsible for embryo-foetopathies. The Australian ophthalmologist MacAlister Gregg was the first to hypothesise, in 1941, a relationship between the onset of a per gravidic rubella and congenital cataract. The serological screening for rubella which is mandatory on early pregnancy allows to identify the initial serological status of the pregnant woman. Potential embryo-foetopathy should therefore be suspected in case any delayed intrauterine growth associated to a heart abnormality is observed in the foetus. Chickenpox is an uncommon disease in women during pregnancy. For the mother, complications are mainly of pulmonary type (in about 10% of the cases), and potentially life-threatening. Before 24-week amenorrhoea, the fœtal transmission (estimated to approximate 6%) may be responsible for a congenital varicella syndrome in about 2% of cases. Perinatal chickenpox due to peripartum transmission induces in about 25% of the cases a neonatal chickenpox potentially serious and sometimes fatal; this risk is essentially associated to an eruption in the mother, occurring during the period from 5 days before delivery to 2 days after. Bacterial infections remain the major concern for paediatric obstetricians since they always constitute a frequent risk for perinatal morbidity and mortality (3^rd cause of mortality). In all studies on maternal-foetal bacterial infections, the streptococcus B was shown to be the principal germ. A significant regression of the mortality is observed (30-90% in the 1970s and 5-15% currently), in relation with strategies of detection during pregnancy, such as vaginal sampling between 35 and 37 weeks of amenorrhoea with a screening for streptococcus B, and perpartum prophylactic antibiotherapy in infected women.