Before delivery (around the 36. week) a vaginal swab can be taken to test for GBS, a common bacterial that colonizes the vagina. Rarely it can be transmitted to the infant during delivery and cause severe infections, e.g. pneumonia, meningitis or osteomyelitis. If a woman is a know carrier she will be offered an antibiotic (usually penicillin) during the last phase of labor. If the status is not known, then the antibiotic will be offered only during special situations, e.g. prolonged rupture of membranes (PROM) or fever.