Reference values for C-reactive protein and procalcitonin at term pregnancy and in the early postnatal period.

Background: Early recognition of sepsis and prompt treatment improves patient outcome. C-reactive protein is a sensitive marker for tissue damage and inflammation, but procalcitonin has greater specificity for bacterial infection. Limited research exists regarding the use of C-reactive protein and procalcitonin at term pregnancy and the immediate postpartum period.

Aim: This study sought to define reference values for C-reactive protein and procalcitonin at term and the early postnatal period.

Methods: A prospective cross-sectional study was performed in a university teaching hospital. Venous blood was collected from healthy women ( = 196), aged between 19 and 45 years with an uncomplicated singleton pregnancy, at term (37-40 weeks' gestation) and on day 1 and day 3 postpartum for the measurement of C-reactive protein and procalcitonin.

Results: The reference population comprised of 189 participants: term pregnancy ( = 51), postpartum day 1 vaginal delivery ( = 70) and caesarean section ( = 38) and day 3 (caesarean section,  = 30). The maximum procalcitonin value at term pregnancy was 0.1 μg/L. On day 1 postpartum, 90% and 86.8% of procalcitonin results for vaginal delivery and caesarean section, respectively, were below the decision-threshold of 0.25 μg/L. The specificity of procalcitonin to rule out infection in the reference population was 91.5%.

Conclusions: Reference values for procalcitonin were established in a well-characterized population of healthy pregnant women at term and immediately postpartum. The variability of C-reactive protein limits its clinical utility in the assessment of systemic sepsis. Application of the procalcitonin cut-off of 0.25 μg/L in this population will be a valuable adjunct to clinicians ruling out infection in pregnancy and postpartum.