Searching for a biochemical correlate of critical illness in obstetrics: a descriptive study of maternal lactate in patients presenting for acute care in pregnancy

Abstract

Obstetric physiology may alter lactate metabolism and affect the ability to use lactate as a discriminator of critical illness in pregnancy. This prospective, cross-sectional study describes venous lactate levels in women presenting for acute care during pregnancy as well as characteristics associated with elevated lactate. Obstetric patients >20-week gestation presenting for acute evaluation were included and a venous lactate sample was drawn for each patient. Elevated lactate was defined as >= 2 mmol/L. One hundred two women were enrolled and venous lactate samples were obtained for 100 participants. Median lactate level was 1.22 (IQR 0.95-1.49) and 86% of patients had normal lactate. Six patients presented with infectious complaints, none of whom had sepsis or elevated lactate. Of the 14 patients with elevated lactate, all presented with labor complaints and 10 (71.4%) were admitted in labor. Elevated lactate level was significantly associated with labor complaints and admission in labor (p < .01). Thus, lactate may not be able to discriminate severe infection consistently in pregnancy as it is confounded by labor. Further research is necessary to clarify how lactate may be used more effectively in pregnant patients and to identify alternate strategies for sepsis screening.