Fig. 1.

Flowchart of the study. *In case subfertility is reported, the participants’ medical files will be requested to verify the cause of subfertility. CSI = Chlamydia Screening Implementation. NECCST = Netherlands Chlamydia Cohort Study. CT = Chlamydia trachomatis. PCR = Polymerase chain reaction. IgG = Immunoglobulin G. CT-positive = at least one positive outcome, either a positive CSI CT Polymerase Chain Reaction (PCR) result, a self-reported CT-infection or CT IgG presence. CT-negative = Never tested positive during CSI, no self-reported CT-infection and no CT IgG presence