However, if the baby is born prematurely, especially before 32 weeks of pregnancy, then the mother's antibodies are not transferred across the placenta and the baby is at much greater risk of serious GBS disease if infected before or during birth. Early onset disease occurs most often in premature babies and after complications of labor and delivery. Early onset disease is a combination of pneumonia and septicemia or infection of the blood. In many cases, the baby is infected before birth because of spread of the bacteria fromthe birth canal into the amniotic fluid. Such babies almost always have severe pneumonia causing very marked respiratory distress which is complicated by the serious blood infection which causes shock .
Symptoms are often present at birth or develop within the first hours of life.
If the baby catches the bacteria from the birth canal during labor or delivery, the symptoms may not develop until a few days after birth and may present as pneumonia, blood stream infection, or meningitis, or a combination of illnesses. Late onset GBS disease occurs between 8 days and 3 months of age. It may consist of blood stream infection by itself, meningitis, pneumonia, or joint infection. Symptoms depend on which organ of the body is infected. Treatment of all GBS infections are with antibiotics given by vein, usually for at least two weeks.