PTB and STIs in pregnant adolescents

New research suggests that certain sexually transmitted infections (STIs), such as Trichomonas vaginalis and Neisseria gonorrhea, may contribute to a higher risk of adverse pregnancy outcomes and preterm birth (PTB) in adolescents.

The retrospective study, published in Infectious Diseases In Obstetrics and Gynecology, analyzed data from a large cohort of adolescent pregnancies and found that early STI detection could play a crucial role in lowering adverse pregnancy outcomes in adolescents.

However, because the median age of participants was 18 years, the authors cautioned that the results may not be generalizable to the entire adolescent population.

Data were collected using electronic medical records and included pregnant adolescents between the ages of 13 and 19 with positive STI test results. The clinical study ultimately included data on 739 deliveries from March 2010 to December 2014.

For the purpose of the analysis, the authors defined PTB as a delivery between 20 0/7 and 36 6/7 weeks of pregnancy. They identified chorioamnionitis as “a heterogeneous group of conditions that may include inflammation and/or infection of the amnion and/or chorion.” 

The researchers noted that chorioamnionitis diagnoses were established during labor or through manual chart reviews. Diagnoses in labor occurred in women who displayed classical signs of chorioamnionitis, such as fever and uterine tenderness. Diagnoses were positive with ICD-9 658.4 and 762.7 included in the electronic medical record, or if the criteria were noted during chart review.

Prevalence of any STI during pregnancy was 16.5% (n=122) and did not definitively lead to PTB or chorioamnionitis. A Chlamydia trachomatis diagnosis occurred in 13.1% (n=97) and prevalence of T. vaginalis was 3.7% (n=27). The PTB rate was 18.8% (n=139) and chorioamnionitis occurred in 15.2% (n=112) of patients.

Researchers found a significant relationship between T. vaginalis and adverse pregnancy outcomes. In fact, patients with a diagnosis of T. vaginalis were twice as likely to be diagnosed with chorioamnionitis, and thus more likely to experience adverse pregnancy outcomes than those not diagnosed (aPR: 2.19, 95% CI 1.26-3.83).

The results did not indicate an association between STI during adolescent pregnancy and PTB. However, they did show an association between T. vaginalis and increased risk of chorioamnionitis. That association was strongest when detected before the third trimester, suggesting that screening for T. vaginalis with a sensitive DNA-based test should be considered early in adolescent pregnancy. The theory is that longer exposure to T. vaginalis may create an environment conducive to chorioamnionitis. If this is true, earlier screening and treatment may be useful, although the results of this study do not prove causation.  

These findings underscore the importance of vigilance in STI screening during adolescent pregnancies and indicate that ob/gyns should consider adding universal T. vaginalis screening in this high-risk population.