C-reactive protein at 11-13 weeks' gestation in spontaneous early preterm delivery

Objective: To examine the potential value of maternal serum level of C-reactive protein (CRP) in the first trimester of pregnancy in the prediction of spontaneous early preterm delivery. Methods: Maternal serum concentration of high-sensitivity CRP at 11-13 weeks' gestation was measured in a case-control study of singleton pregnancies delivering phenotypically normal neonates, including 30 cases with spontaneous delivery before 34 weeks, with 15 cases presenting with contractions and 15 cases presenting with preterm premature rupture of membranes, and 90 matched controls delivering after 37 weeks. The median multiple of the median (MoM) serum CRP in the two outcome groups was compared. Results: The median serum CRP MoM was not significantly different in the spontaneous early preterm delivery group compared to the term delivery group (1.101, IQR = 0.572-1.985 vs. 0.975, IQR = 0.577-1.923; p = 0.813). The prevalence of CRP MoM above the 75th percentile was not significantly different between the early preterm delivery group compared to the term delivery group (26.7 vs. 24.4%; p = 0.811). In the preterm delivery group, the median serum CRP MoM in those presenting with contractions was not significantly different from those presenting with PPROM (1.175, IQR = 0.403-2.122 vs. 1.027, IQR = 0.659-1.940; p = 0.713). High-sensitivity CRP did not significantly improve prediction for preterm delivery over regular CRP. Conclusions: Measurement of maternal serum CRP at 11-13 weeks is unlikely to be useful in screening for spontaneous early preterm delivery.