Background Studies have shown an association between Chlamydia trachomatis infection (chlamydia) and an increased risk for tubal factor infertility (TFI) in women. To assess if this association also result in fewer pregnancies, we aimed to investigate the proportion of pregnancies in women with and without a previous chlamydia infection in women participating in the Netherlands Chlamydia Cohort Study (NECCST).

Methods NECCST is a cohort of 5704 women of reproductive age all tested for chlamydia by PCR in a chlamydia screening study between 2008–11. Women were re-invited for NECCST in 2015–16. Chlamydia-status (positive/negative) was defined using results from the screening, chlamydia IgG presence in serum and/or self-reported chlamydia infections. Data on pregnancies was collected via questionnaires in 2015–16 and 2017–18. Pregnancies, intended and unintended, were compared between chlamydia positive and chlamydia negative women who ever tried to become pregnant using logistic regression analyses.

Results Of 5704 women enrolled, 1717 (30.1%) were chlamydia positive and 3146 (55.2%) tried to become pregnant or had been pregnant at least once. In preliminary results, of those 3146 women, 980 (31.2%) were CT positive and 2166 (68.8%) were CT negative. Of CT positive women, 90% (n=882) got pregnant compared to 91% (n=1973) of CT negative women, p=0.329. Excluding unintended pregnancies, CT positive women got pregnant less often (82% versus 89%, p<0.001) and aOR 0.56 (95%CI 0.42–0.74, p<0.001) corrected for age.

Conclusion The proportion of women who were ever pregnant did not differ between chlamydia positive and negative women. However, an intended pregnancy was less common in women with a previous chlamydia infection.

Disclosure No significant relationships.