C-reactive protein in preterm labour: association with outcome of tocolysis and placental histology

Tocolytics were administered in 66 consecutive women in uncomplicated preterm labour with intact fetal membranes (53 singleton and 13 twin pregnancies). C-reactive protein (CRP), a marker of infection, was determined daily and used retrospectively to investigate the role of subclinical infection in preterm labour and to predict the efficacy of tocolysis and the development of a clinical perinatal infection. CRP was also determined in 66 women in uncomplicated labour at term (53 singleton and 13 twin pregnancies). The placenta was examined for histological evidence of infection in all patients who were delivered before 36 weeks (n = 21) and in all women in the control group (n = 66). Elevated CRP levels were more often found in patients who were refractory to tocolysis, suggesting an underlying infectious morbidity. Placental infection was found in 62% of the preterm delivery group and in 12% of the control group. There was an association between elevated CRP levels and histological evidence of placental infection. However, confounding factors such as urinary tract infections limit the usefulness of the CRP test. Because CRP cannot predict clinical perinatal infection accurately, its clinical relevance is very limited.