Serum procalcitonin concentrations in term delivering mothers and their healthy offspring: a longitudinal study.

BACKGROUND The reported sensitivities and specificities of procalcitonin (PCT) concentrations for the diagnosis of neonatal infection vary widely. A postnatal increase of PCT has been observed in healthy term newborns with a peak at approximately 24 h of age, and many questions remain regarding maternal and perinatal factors that may influence the normal PCT kinetics during the immediate postnatal period. METHODS We prospectively investigated the association between the serum PCT values obtained from 121 mothers at delivery and serum PCT in their healthy, term offspring at birth as well as at 24 and 48 h of age. We also analyzed whether obstetric and perinatal factors would alter maternal and neonatal PCT response. RESULTS PCT concentrations in the babies at birth were significantly higher than in the mothers (P <0.0001), with even larger differences at 24 and 48 h of age. None of the variables identified from maternal and perinatal histories had a significant effect on maternal PCT response. In the healthy neonate, the variables that significantly affected the concentration of PCT at birth were the mothers' PCT (P <0.01), maternal group B streptococcus colonization (P <0.05), and rupture of membranes >/=18 h (P <0.01). The coefficient of linear correlation between the mother's PCT concentration and that of the baby at birth was 0. 32 (P <0.01). The only variable that significantly altered the PCT concentration at both 24 (P <0.01) and 48 (P <0.01) h of age was rupture of membranes >/=18 h. Nonetheless, the PCT response observed during the 48-h period after birth among healthy babies born to mothers with risk factors for infection was well below that reported previously among age-matched neonates with sepsis. CONCLUSIONS The postnatal increase of PCT observed in the healthy neonate with peak values at 24 h of age most likely represents endogenous synthesis. In estimating the sensitivities and specificities of PCT for diagnosis of sepsis throughout the initial 48 h of life, it is important to consider the normal PCT kinetics and the pattern(s) of PCT response in the healthy neonate.