Ureaplasma urealyticum incriminated in perinatal morbidity and mortality.

Perinatal morbidity and mortality are associated with colonization of the chorionic surface of the placenta by Ureaplasma urealyticum or Mycoplasma hominis or both. These organisms are more strongly associated with unfavourable gestational outcome than group B streptococci. Chlamydia trachomatis does not appear to be important in the etiology of reproductive casualties. The mechanisms linking the mycoplasmas to perinatal disorders and death are not clear but merit investigation.