C-reactive protein during normal pregnancy.

Serum C-reactive protein (CRP) is determined in a prospective longitudinal study of 60 low-risk pregnant women. CRP is also measured in umbilical-cord blood after delivery. The serum CRP concentrations seem to be independent of pregnancy and gestational age. The 95th percentile is estimated to be 20 mg/l, and this value is considered as the upper limit of normal. A rise in CRP level is considered more predictive of infection than a determination of a single high value. CRP does not cross the placental barrier, and may therefore be useful in diagnosing infections in newborns.