Prevalence of Chlamydia and Gonorrhea Among Pregnant Adolescents Screened in the Third Trimester Using a Urine PCR Test: A Retrospective Review

Objective: Our study assessed the rate of new and recurrent Chlamydia trachomatis and Neisseria gonorrhoeae infections in the third trimester at an adolescent obstetrics clinic.Method: Between October 2016 and June 2020, routine third-trimester screening for C. trachomatis and N. gonorrhoeae was implemented according to new Canadian recommendations. Urine nucleic acid amplification was performed. Patient records were reviewed retrospectively, and demographic data; pregnancy and delivery characteristics; and information on screening at presentation to care, third-trimester screening (33-38 weeks), and other STI testing was recorded.Results: A total of 115 adolescents (mean age 17.90 +/- 1.43 y) with 125 pregnancies presented for care. Twenty-three pregnancies were excluded (12 transferred out and 11 experienced a pregnancy loss). At presentation, screening was performed in 100 of 102 pregnancies: 64 of 100 at <13 weeks, 32 of 100 at 13-27 weeks, and 4 of 100 at 28-30 weeks. Nine tested positive for C. trachomatis and none tested positive for N. gonorrhoeae. In the third trimester, there were 3 positive C. trachomatis tests, but all were indicated: test of cure was due for 1 patient, 1 patient had a new sexual partner, and 1 patient presented with symptoms. The remaining 89 of 102 pregnancies were screened (with no other indication) and none were positive for C. trachomatis or N. gonorrhoeae. Ten patients could not be sampled (5 missed, 4 preterm deliveries, and 1 non-compliant with testing).Conclusion: No cases of C. trachomatis or N. gonorrhoeae infection were identified on third-trimester screening in our study. Adolescent obstetrics providers implementing Canadian screening guidelines may want to monitor their screening results to determine whether their yield warrants universal implementation.