The Netherlands Chlamydia cohort study (NECCST) protocol to assess the risk of late complications following Chlamydia trachomatis infection in women

Abstract

Background Chlamydia trachomatis (CT), the most common bacterial sexually transmitted infection (STI) among young women, can result in serious sequelae. Although the course of infection is often asymptomatic, CT may cause pelvic inflammatory disease (PID), leading to severe complications, such as prolonged time to pregnancy, ectopic pregnancy, and tubal factor subfertility. The risk of and risk factors for complications following CT-infection have not been assessed in a long-term prospective cohort study, the preferred design to define infections and complications adequately.MethodsIn the Netherlands Chlamydia Cohort Study (NECCST), a cohort of women of reproductive age with and without a history of CT-infection is followed over a minimum of ten years to investigate (CT-related) reproductive tract complications. This study is a follow-up of the Chlamydia Screening Implementation (CSI) study, executed between 2008 and 2011 in the Netherlands. For NECCST, female CSI participants who consented to be approached for follow-up studies (n = 14,685) are invited, and prospectively followed until 2022. Four data collection moments are foreseen every two consecutive years. Questionnaire data and blood samples for CT-Immunoglobulin G (IgG) measurement are obtained as well as host DNA to determine specific genetic biomarkers related to susceptibility and severity of infection. CT-history will be based on CSI test outcomes, self-reported infections and CT-IgG presence. Information on (time to) pregnancies and the potential long-term complications (i.e. PID, ectopic pregnancy and (tubal factor) subfertility), will be acquired by questionnaires. Reported subfertility will be verified in medical registers. Occurrence of these late complications and prolonged time to pregnancy, as a proxy for reduced fertility due to a previous CT-infection, or other risk factors, will be investigated using longitudinal statistical procedures.DiscussionIn the proposed study, the occurrence of late complications following CT-infection and its risk factors will be assessed. Ultimately, provided reliable risk factors and/or markers can be identified for such late complications. This will contribute to the development of a prognostic tool to estimate the risk of CT-related complications at an early time point, enabling targeted prevention and care towards women at risk for late complications.Trial registrationDutch Trial Register NTR-5597. Retrospectively registered 14 February 2016.

Relation betweenChlamydia trachomatisinfection and pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility in a Dutch cohort of women previously tested for chlamydia in a chlamydia screening trial

“…Thus, while the largest risk for PID following a chlamydia infection was in the year of infection, the majority of PIDs occurred thereafter. Lastly, to draw conclusions on a possible association between chlamydia and ectopic pregnancy, which remains inconclusive also in previous studies,9 26 longer follow-up of NECCST will be needed 20…”

“…NECCST is a cohort of women of reproductive age to be followed until 2022. The design has been described previously 20. Briefly, women between 16 and 29 years participated in 2008–2011 in the CSI 14.…”

“…To study chlamydia-related sequelae and risk factors, the Netherlands Chlamydia Cohort Study (NECCST) was initiated in 2015. NECCST is an ongoing cohort study among Dutch women of reproductive age and a follow-up study of the 2008–2011 Chlamydia Screening Implementation programme (CSI) in which all women were tested for chlamydia 20. We estimated risks of PID, ectopic pregnancy and TFI up to 8 years after chlamydia infection in women taking into account sexual risk behaviour, demographics and lifestyle factors.…”

Pregnancies and Time to Pregnancy in Women With and Without a Previous Chlamydia trachomatis Infection

“…The design of NECCST has been described previously. 13 Briefly, in 2008 to 2011, women between the ages of 16 to 29 years participated in the population-based chlamydia screening implementation study (CSI). 2 During CSI, women received annual invitations for chlamydia nucleic acid amplification tests (NAATs).…”

Diagnostic value of detection of serum β‑HCG and CT‑IgG combined with transvaginal ultrasonography in early tubal pregnancy

“…The early diagnostic methods of tubal pregnancy include transvaginal ultrasonography, laparoscopy, detection of progesterone, serum β-human chorionic gonadotropin (β-HCG) and other biochemical indexes. The study of the correlation between Chlamydia trachomatis immunoglobulin G (CT-IgG) antibody and salpingitis, tubal pregnancy and tubal infertility has been reported ( 2 , 3 ). The clinical manifestations of early tubal pregnancy are not specific and similar to the symptoms of early intrauterine pregnancy and abortion, and in addition to the individual differences of pregnant women, sometimes the single detection method is not enough to diagnose tubal pregnancy.…”