Lactate and Procalcitonin Levels in Peripartum Women with Intraamniotic Infection.

OBJECTIVES Serum biomarkers are used to diagnose and manage severe infections, but data on their utility during labor are limited. We compared lactate and procalcitonin levels in women with and without intraamniotic infection to determine if they are useful biomarkers for infection during labor. STUDY DESIGN We performed a prospective observational cohort study of term, singleton pregnancies admitted with planned vaginal delivery in 2019 at a university medical center. Lactate and procalcitonin levels were drawn in early labor, within 2 hours following delivery, and postpartum day 1. Women with intraamniotic infection additionally had lactate and procalcitonin levels drawn following intraamniotic infection diagnosis. Samples were processed immediately in the hospital clinical laboratory. Primary outcome was mean lactate level following delivery. Secondary outcomes were lactate and procalcitonin levels at other time points. Comparisons based on infection status were performed using multivariate linear regression. RESULTS 22 women with intraamniotic infection and 29 uninfected women were included. Early labor mean lactate level (1.47 vs 1.49 mmol/L) and mean procalcitonin level (0.048 vs 0.039 ng/mL) did not differ and were normal in uninfected and intraamniotic infection groups. Mean lactate level was highest following delivery for women in uninfected and intraamniotic infection groups (2.00 vs 2.33 mmol/L, adjusted p=0.08, 95% CI 0.98-1.53). Lactate level returned to normal by postpartum day 1 and did not significantly differ based on the infection status at any time point in adjusted models. Procalcitonin level following delivery was higher among women with intraamniotic infection versus without infection (0.142 vs 0.091 ng/mL, adjusted p=0.03). Procalcitonin level rose further in both intraamniotic infection and uninfected groups on postpartum day 1 (0.737 vs 0.408 ng/mL, adjusted p=0.05). CONCLUSIONS Lactate level is not significantly elevated in intraamniotic infection above the physiologic increase at delivery observed in women without infection. Procalcitonin level is elevated at delivery in women with intraamniotic infection and warrants further investigation as a peripartum infection marker.