Comparing Specimen Collection Techniques to Screen for Sexually Transmitted Infections in Pregnant Women: A Pilot Study

Chlamydia trachomatis and Neisseria gonorrhoeae are the two most commonly reported infectious diseases in the United States. Their role in pregnancy-related comorbidities such as spontaneous abortion, preterm labor, chorioamnionitis, preterm premature rupture of membranes, and perinatal infection is complicated as data is conflicting. Many reports suggest increased risks of adverse pregnancy outcomes in the presence of C. trachomatis and N. gonorrhoeae infections. However, there are also several studies that have failed to demonstrate an increased risk. Despite conflicting reports, due to high prevalence of these infections and association with pregnancy-related co-morbidities, the Center for Disease Control (CDC) recommends screening for C. trachomatis and N. gonorrhoeae in high-risk populations at initiation of prenatal care, and again during the third trimester to ensure infections are treated quickly and resolved prior to birth.

In the non-pregnant female population, there are many ways to screen for C. trachomatis and N. gonorrhoeae pelvic infections, including bacterial culture, direct fluorescent antibody testing, deoxyribonucleic acid (DNA) probe, enzyme immunoassay, or ribonucleic acid (RNA) amplification. These various testing modalities can be applied to urine, or vaginal or endocervical samplings. RNA assays and DNA probes are currently the least expensive and most accurate way of screening, and are therefore the most routinely used.

At OhioHealth Doctors Hospital (DH) Women's Health Center, pregnant patients are screened for sexually transmitted infections (STI) using the Hologic Aptima Chlamydia trachomatis and the Neisseria gonorrhoeae assays, which are second generation nucleic acid amplification assays (NAATs). Samples are collected using the Hologic Aptima Unisex Specimen Collection Kit for Endocervical and Male Urethral Swab Specimens. These swabs are specifically designed for cervical swab collection techniques. Per standard of care at DH and CDC recommendations, patient endocervical swabs are collected at the patient's initial prenatal visit and during her third trimester appointment (approximately 36 week gestation) to test for infection.

In non-pregnant women, the vaginal specimen collection kit has been shown to be just as effective at detecting pelvic infections of C. trachomatis and N. gonorrhea using RNA assays. There are many benefits of adopting the use of a vaginal specimen collection kit, as compared to endocervical collection. Vaginal sampling can be performed without a speculum exam in asymptomatic women. In addition to being a less invasive test, the vaginal swab may reduce testing costs, by eliminating the use of collection tools (such as disposable speculums) that are required during an endocervical collection; avoiding the endocervical collection procedure may also reduce the overall office visit time. Additionally, patients could be instructed to collect a vaginal sample themselves. This may increase patient satisfaction, privacy, and comfort. In fact, several publications have reported patient preference for a self-collected vaginal swab vs. an endocervical swab.

Few studies have evaluated the used of vaginal or introital swabbing techniques for detection of infectious microorganisms during pregnancy, but the published data is favorable for the use of a vaginal swab. Thus, more data is needed to compare the use of vaginal vs. endocervical swabs to detect infections in pregnant women. The objective of this study is to compare detection of sexually transmitted infections in pregnant women by collecting samples using both the Hologic Aptima Vaginal Swab and the Unisex Specimen Collection Kit for Endocervical and Male Urethral Swab.