Effect of antenatal Chlamydia trachomatis and Neisseria gonorrhoeae screening on postdelivery prevalence and vertical transmission in Gaborone, Botswana: findings from an exploratory study

Objectives: Chlamydia trachomatis and Neisseria gonorrhoeae are common sexually transmitted infections (STIs). Untreated infection in pregnancy can result in adverse neonatal outcomes, including vertical transmission. Screening for these infections is not routine in low- and middle-income countries (LMICs).

Methods: The Maduo Study was a non-randomised cluster crossover trial in Botswana to provide preliminary data on the effect of antenatal C. trachomatis and N. gonorrhoeae screening and treatment on postdelivery prevalence and vertical transmission to infants. Pregnant women asymptomatic for STIs were enrolled at four clinics (seven clusters). The intervention arm received C. trachomatis and N. gonorrhoeae screening at first antenatal care, third trimester and postdelivery. The standard-of-care arm received postdelivery screening only. Infants of women with a positive test postdelivery in both arms were screened. A cluster-level analysis was performed to compare the risk of postdelivery infection between intervention and standard-of-care arms.

Results: The study enrolled 500 women; 206 (82.1%) and 187 (75.1%) were retained in the intervention and standard-of-care arms, respectively and screened ≤12 weeks postdelivery. C. trachomatis prevalence in the intervention arm reduced from 22.7% at first antenatal care to 1.0% postdelivery. N. gonorrhoeae prevalence reduced from 1.2% at first antenatal care to 0% postdelivery. The risk of C. trachomatis and/or N. gonorrhoeae was lower in the intervention arm postdelivery (0.6%) compared with the standard-of-care arm (15.7%); adjusted risk difference: -14.7% (95% CI -23.0%, -6.4%). Among 26 infants born to women with either infection postdelivery, 10 (38.5%) tested positive (C. trachomatis: 9; N. gonorrhoeae: 1).

Conclusions: Postdelivery prevalence of C. trachomatis was significantly lower among pregnant women in Botswana who received diagnostic antenatal screening. Among women with C. trachomatis and/or N. gonorrhoeae postdelivery, more than one-third transmitted the infection to their infants. This exploratory study suggests antenatal STI screening has the potential to reduce infection in newborns in similar LMIC settings.

Trial registration number: NCT04955717.