The influence of group B streptococcal-carriership on pregnancy outcome

762 women were screened for GBS-carriership in the first trimester of pregnancy. The mean age of carriers was 27.2 years. Follow-up was performed in 64 initially positive and 97 negative cases. Persistent carriership was the most important determinant for neonatal GBS-acquisition. Race, birth-weight, gestational-age, interval between rupture of the membranes and birth could not be associated with GBS-carriership or neonatal acquisition. The number of neonates with fetal distress was significantly higher amongst those born to all GBS-carriers; the number of S.G.A.-infants was significantly elevated amongst those born to permanently positive women. Vertical transmission was found in 86% of the mother-infant pairs. GBS serotype III and Ib were predominant. Serotype III was significantly more isolated from non-caucasian women. The transmission frequency of all types was equal (46%), except for type IIc (22%). None of the serotypes was especially associated with fetal distress or smallness for gestational age.