Chorioamnionitis and colonization of the newborn infant with genital mycoplasmas.

To study the role of Mycoplasma hominis and T-mycoplasmas (Ureaplasma urealyticum) in chorioamnionitis, we obtained culture from 249 puerperal women and their babies. The placentas were examined histologically. Infants whose placentas showed inflammation (chorioamnionitis) had cultures positive for T-mycoplasmas more frequently (37.5 per cent) than those with normal placentas (19.0 per cent) (P = 0.021). Colonization with M. hominis was found in 16.0 per cent of the babies and was not significantly associated with chorioamnionitis. Material colonization with mycoplasmas was more frequent (73.4 per cent) and was not correlated with placental inflammation. We conclude that a substantial proportion of cases of chorioamnionitis may be caused by prenatal infection with T-mycoplasmas. The fact that these organisms are not highly virulent could explain the frequent finding of inflammed placentas from otherwise normal pregnacies. No adverse clinical effects of the placental lesions or of mycoplasmal colonization could be detected in this small study.