(1195) Effect of intrapartum antibiotic prophylaxis on systemic maternal inflammation during labor induction

This prospective cohort study enrolled women age 18-45 years, term, and undergoing labor induction (IOL) with cervical Foley and oxytocin. Exclusion criteria were known fetal demise and multiple gestation. We drew blood samples prior to IOL and 6-12 and 18-24 hours (h) after IOL start and compared pro-inflammatory cytokine levels (IL-1α, IL-1β, IL-6, IL-8, GM-CSF, IFN-g, MCP-1, and TNF-α) in those who received IAP versus those who did not. We used linear mixed models to evaluate differences in labor cytokines between IAP groups over time, controlling for obesity, parity, race/ethnicity, chronic hypertension, preeclampsia and diabetes.

Results:

113 women (n=59 did not receive IAP and n=54 received IAP) were recruited. Cytokine concentrations significantly increased between pre-labor and 12-24h post-IOL measures with the exception of IFN-g, IL-1α and TNF-α (Figure).  Overall, patients who received IAP had higher mean concentrations of IFN-g (unadjusted geometric mean ratio [GMR] 1.27 [95% CI 1.05, 1.55]) and lower levels of TNF- α (unadjusted GMR 0.87 [95% CI 0.76, 0.99]; Table). IL-1α levels did not differ by IAP status pre-labor but were 80% greater for those with IAP at 6-12h post-IOL. TNF-α concentrations at 6-12h were significantly lower in those who received IAP compared with those who did not (GMR 0.84 [95% CI 0.71, 0.99]).  

Conclusion:

Intrapartum TNF-α concentration was lower in those who received IAP for GBS compared with those who did not, while IFN-g, IL-1α concentrations were higher. Given the known effects of these cytokines on uterine contractility and labor, this could suggest a mechanism by which prophylactic antibiotics during labor induction may influence uterine activity and the risk of abnormal labor.