In a prospective study on genital infections, the influence of Chlamydial cervicitis on pregnancy outcome was evaluated. In eleven women with Chlamydial cervicitis perinatal outcome was recorded, the placenta was examined and the newborns were screened for Chlamydial conjunctivitis. They were compared with 13 women who were negative for Chlamydia and were delivered immediately after a Chlamydia positive woman. Compared to negative women, women with Chlamydia cervicitis were younger and presented for antenatal care at a later gestational age (difference not significant) and started having sexual intercourse at an earlier age (P less than 0.02). There was a significant association between Chlamydial infection and chorioamnionitis, lower birth weight and severe neonatal infection (P less than 0.05); but a contribution from concomitant genital pathogens could not be completely ruled out. Therefore a screening program for Chlamydia should include screening for other genital infections. While almost all cases of Chlamydia could have been suspected by this technique, a screening based on lactobacillary grades in Pap smears might be helpful for this purpose, even more so because it also facilitates tracing other genital pathogens. Detection of Chlamydial antigen from conjunctival swabs taken immediately after birth did not adequately reflect the risks of neonatal infection in this small group.