[Chlamydia trachomatis in pregnant women in the county of Vestsjaelland. Prevalence, prevention of perinatal transmission and cost-effectiveness of screening].

The prevalence of genital Chlamydia trachomatis (CT) in pregnant women and the perinatal transmission after treatment was investigated. An analysis of the cost-effectiveness of introducing a screening program among women at risk of having CT was made. Out of 339 pregnant women 2.9% had cervical CT. CT-positive women were treated with erythromycin. CT-positive women were significantly younger than CT-negative women and the odds ratio (OR) of having CT if nulliparous was 3.35. The CT-prevalence was 6.6% among women younger than 25 years and 1.6% among women 25 years or older (p = 0.0163). OR of having CT if younger than 25 years was 4.3. The young women were significantly younger at sexual début. None of the children of women treated for CT during pregnancy developed neonatal CT-conjunctivitis. The screening of women younger than 25 years was considered to be cost-effective. It is concluded that women younger than 25 years are at risk of having CT. Treatment of CT-positive women with erythromycin during pregnancy seems to be effective in eradicating this microorganism and thus preventing perinatal transmission and neonatal CT-conjunctivitis. It therefore seems rational to screen all pregnant women under the age of 25 years for cervical CT, especially in high risk areas.