Risk factors for Chlamydia trachomatis infection of the cervix: a prospective study of 2000 patients at a family planning clinic.

Two thousand and thirty-four patients attending a family planning clinic were tested for the presence of Chlamydia trachomatis infection of the cervix. The incidence of infection was 17.5%. Pregnant patients had a higher incidence of infection (23%), than nonpregnant patients (16.8%; p less than 0.05), and in the former this was not related to age. In nonpregnant women age was found to be an important determinant of infection rate, 22% in the 20 and under age group, and 9% in those over 25 years (p less than 0.01). There was a higher rate of infection in those with abnormal cervical smears, and in those with a coincident sexually transmitted infection; this was not statistically significant. Risk factors for acquiring this infection were identified as patients with more than five life time partners, those 20 years old or less, and pregnant patients, regardless of age or number of partners.