Identifying the Impact of Chlamydia trachomatis Screening and Treatment on Mother-to-Child Transmission, and Respiratory Neonatal Outcomes in Mexico

<i>Chlamydia trachomatis</i> (<i>C. trachomatis</i>) screening and treatment in pregnancy allows the opportunity to reduce adverse pregnancy and neonatal outcomes worldwide. Although <i>C. trachomatis</i> infection is easily treated and cured with antibiotics, only some countries have routine pregnancy screening and treatment programs. We therefore evaluated whether just one maternal screening for <i>C. trachomatis</i> is enough to prevent adverse pregnancy and negative neonatal outcomes. Among the 4087 first-time gynecological-obstetric consultations granted at the National Institute of Perinatology in 2018, we selected the study population according to a case-cohort design. Antenatal <i>C. trachomatis</i> screening and treatment interventions were performed on 628 pregnant women using COBAS^® TaqMan CT. <i>C. trachomatis</i> DNA was also detected in samples from 157 infants of these mothers. In the maternal cohort, incidence of <i>C. trachomatis</i> infection was 10.5%. The vertical transmission rate was 1.5% for the cohort of mothers who tested positive for <i>C. trachomatis</i> and received treatment, and 29.7% for those with a negative test. By evaluating symptomatic neonatal infection, the hazard rate of perinatal pneumonia was 3.6 times higher in <i>C. trachomatis</i>-positive babies than in <i>C. trachomatis</i>-negative babies. Despite the low rate of mother-to-child transmission in women positive for <i>C. trachomatis</i>, possible maternal infection that is not detected in pregnancy significantly increases the risk of neonatal infection with consequent perinatal pneumonia.