Type-specific streptococcal antibodies in amniotic fluid.

Type-specific antibodies against group B streptococcal and pneumococcal capsular antigens were measured in 68 amniotic fluid samples from healthy women between 16 and 20 weeks of pregnancy. Mean antibody levels ranged from 0.13 to 0.61 microgram/ml, with few samples having greater than 1 microgram/ml against any antigen. The role of antibodies in protection against intrauterine infection is discussed.