Prenatal Chlamydia Exposure and Early Neonatal Respiratory Failure in Very Preterm Infants

This study aimed to investigate the association between prenatal <i>Chlamydia</i> exposure and early neonatal respiratory failure (NRF) in very preterm infants (VPIs).This population-based cohort study utilized birth data submitted by 50 states and the District of Columbia to the National Vital Statistics System database in the United States. The study included all VPIs with a gestational age of 24 to 31 weeks from January 1, 2021, to December 31, 2022. Infants exposed to <i>Chlamydia</i> were compared with unexposed infants (no <i>Chlamydia</i> exposure) selected through propensity score matching at a 1:2 ratio, adjusting for confounding factors. The primary outcome was NRF, defined as the requirement for assisted ventilation for more than 6 hours, as recorded in the database.After propensity score matching, 2,757 <i>Chlamydia</i>-exposed infants and 5,507 no <i>Chlamydia</i>-exposure infants were compared. Infants with <i>Chlamydia</i> exposure had a significantly higher relative risk of NRF compared to no <i>Chlamydia</i>-exposure infants (30.5%, 840/2,757 vs. 25.4%, 1,401/5,507; risk ratio [RR] = 1.20 [95% CI, 1.13-1.29]). Additionally, the risk of assisted ventilation required immediately following delivery was higher in the <i>Chlamydia</i>-exposed group (47.2%, 1,300/2,757 vs. 41.5%, 2,283/5,507; RR = 1.15 [95% CI, 1.10-1.20]). Subgroup analyses by gestational age, sex, and other factors demonstrated consistent results for the primary outcome. Sensitivity analyses, including total infants, 1:1 propensity score matching, and 1:3 propensity score matching, yielded similar findings.Prenatal <i>Chlamydia</i> exposure is significantly associated with an increased risk of NRF in VPIs. Further investigation is warranted to develop intervention strategies aimed at preventing NRF in high-risk infants with prenatal <i>Chlamydia</i> exposure. · NRF remains the leading cause of early neonatal death in VPIs.. · There is limited and inconclusive evidence regarding prenatal Chlamydia and NRF.. · VPIs with Chlamydia exposure had a significantly higher risk of NRF..