Background. We studied the association between the C-reactive protein level in the maternal serum early in the second trimester with that in preterm delivery.
Methods. The present study is a prospective nested case-control study including 84 singleton, preterm deliveries (cases) and 400 singleton, term deliveries (controls), based at the Odense University Hospital, Denmark. These cases were identified from a cohort of 2846 women, monitored from their first prenatal care visit until their delivery. All the participants were examined at enrollment (median 16.3 weeks of gestation). Conventional statistical methods were used for analyses.
Results. We found statistically significant differences in the C-reactive protein levels measured in early pregnancy between the women delivering preterm and those delivering at term. Different statistically significant odds ratios of between 1.7 and 2.0 were calculated, depending on the C-reactive protein level's cut-off value, and ranged from 5.6 mg/l (75th percentile) to 16.4 mg/l (95th percentile). The highest level was achieved at the 85th percentile (7.6 mg/l); odds ratio 2.0 (95%CI, 1.2–3.5).
Conclusion. A high C-reactive protein level at the beginning of a pregnancy is associated with a nearly twofold increased risk of preterm delivery; however, the clinical value at this point is still limited.