Although transmission of Chlamydia trachomatis to infants during vaginal birth can result in conjunctivitis and pneumonitis, there is uncertainty about other adverse effects of chlamydial infection during pregnancy. There is some evidence that it may contribute to adverse complications such as premature rupture of membranes, preterm labor and birth, low birth weight, and still birth. Infection with C. trachomatis is also implicated in postabortal, postcesarean section, and postpartum maternal infections. Treatment of chlamydial infection during pregnancy has proved beneficial in the prevention of neonatal morbidity and is now recommended by the Centers for Disease Control.