Association of Labor and Lactate Levels

Abstract

Background: Lactate is widely used as a marker for sepsis in pregnant and non-pregnant individuals. During an infection, lactate rises both due to increased production and decreased clearance. During labor, hypoxia can be noted in the uterus due to contractions that increase in frequency and magnitude which may also contribute to rising lactate. Thus, this study aimed to determine whether labor affects lactate levels.

Methods: This retrospective observational study reviewed charts of pregnant women who had serum lactic acids drawn during active labor and prior to delivery regardless of whether they ultimately underwent a cesarean section or vaginal birth at Saint Josephs Medical Center (SJMC) in Stockton, CA. Patients were categorized into non-septic and septic groups based on the institutions modified systemic inflammatory response syndrome (SIRS) criteria for pregnant women. Two-sample t-tests were used to compare the mean serum lactic acid, body mass index (BMI), hours of labor at time of lactic acid collection, age, gravida, and para between septic and non-septic groups. A regression analysis was also used to determine any relation between serum lactate levels and the hours of labor that had passed at the time of the serum lactate collection.

Results: Sixty-two patient charts were identified and reviewed. Thirty patients fit the septic group inclusion criteria. There was a statistically significant difference in serum lactate between septic versus nonseptic patients (P = 0.0043, 95% confidence interval (CI): -2.32, -0.45), independent of labor length. There was no relation between serum lactic acid and the hours of labor that had passed at the time of the lab (P = 0.419). There was also no statistically significant difference in the mean BMI (P = 0.18, 95% CI: -0.85, 4.39), hours of labor (P = 0.57, 95% CI: -4.01, 2.24), age (P = 0.44, 95% CI: -1.56, 3.52), gravida (P = 0.91, 95% CI: -1.03, 0.92), or para (P = 0.98, 95% CI: -0.65, 0.63) between the non-septic and septic groups.

Conclusions: The primary results suggest that lactic acid remains an accurate indicator of sepsis status given that septic patients had a significantly elevated mean serum lactate. There was also no correlation between serum lactate and the hours of labor that had passed at the time of the lab collection.

J Clin Gynecol Obstet. 2023;12(3):84-87
doi: https://doi.org/10.14740/jcgo912