Repeat screening for sexually transmitted infection in adolescent obstetric patients.

Objective: To determine if repeat screening for sexually transmitted infection is appropriate for adolescent obstetric patients and to identify any risk factors associated with increased risk of contracting a sexually transmitted infection (STI) during pregnancy.

Methods: We conducted a retrospective review of the medical records of adolescent obstetric patients seen over a five-year period in the Young Prenatal Program at the Hospital for Sick Children (Toronto, Ontario).

Results: Between January 2003 and December 2007, 201 patients with 211 pregnancies attended the Young Prenatal Program. Of the 211 pregnancies reviewed, all patients had screening at baseline for HIV, syphilis, hepatitis B, chlamydia, gonorrhea, and trichomonas; 173 patients were screened in the third trimester, two were tested at another point in the pregnancy because of symptoms, and 161 were screened at their postpartum visit. In 53 pregnancies, STI was diagnosed either during pregnancy or postpartum. Fourteen patients had multiple sexually transmitted infections for a total of 71 infections. Thirty-four infections were diagnosed at baseline, 15 in the third trimester, two because of symptoms, and seven were diagnosed postpartum. In patients who did not develop an STI during pregnancy, the previous use of contraception (excluding condoms), being in a relationship with the baby's father, and living with their partner were identified as significant protective factors against STI. There was a trend towards significance for contracting an STI in patients with a history of abuse, in those with a higher than average number of sexual partners, and in those with a younger than average age of coitarche.

Conclusion: Sexually transmitted infections were diagnosed in 25.1% of adolescent pregnancies (53/211) in our cohort. Of the 71 sexually transmitted infections diagnosed, 22.5% (16/71) were diagnosed on routine third trimester screening. Because of the high rates of STI and the small number of identified risk factors, routine repeat screening in the third trimester for chlamydia, gonorrhea, and trichomonas is warranted in pregnant adolescents.