The purpose of our study was to analyze the efficacy of serum C-reactive protein (CRP), white blood cell count (WBC) and erythrocyte sedimentation rate (ESR) serial evaluations in the prediction of chorioamnionitis in cases of premature rupture of membranes (PROM).
Materials and methods: A group of 80 patients with PROM before 35 weeks' gestation were evaluated prospectively and managed expectantly. We applied the expectant management with the permanent use of tocolysis, antibiotics, steroids, amnioinfusions of artificial amniotic fluid and intravaginal chemotherapeutics. Patients were monitored with frequent vital signs, fetal heart rate evaluation and everyday blood tests as follows: CRP, WBC and ESR. All afterbirths were examined to establish the presence of histologic chorioamnionitis (gold standard of intrauterine infection).
Results: 59 (73.7%) patients had significant chorioamnionitis on histopathology and only 15 of them had clinical chorioamnionitis. Serum CRP serial determinations (definition of abnormal tests: 1) > 1.2 mg/dl; 2) > 2.0 mg/dl; 3) > 1.2 mg/dl and increasing in two consecutive days) were found the most reliable with a sensitivity 1) 91.5%; 2) 85%; 3) 88%, specificity 57%; 76%; 86%, positive predictive value 86%; 90%; 94.5%, negative predictive value 70.5%; 64%; 72% and accuracy 82.5%; 82.5%; 87.5% respectively. The efficacy of WBC (abnormal tests: > 12500/mm3; > 15000/mm3; > 12500/mm3 and increasing in two consecutive days) and ESR (abnormal tests: > 60 mm/h; > 60 mm/h and increasing in two consecutive days) serial evaluations was significantly lower. Moreover, in cases of chorioamnionitis CRP increased above the upper limit of normal 3 days earlier than WBC or ESR.
Conclusions: CRP was found the most reliable indicator of histologic chorioamnionitis and indicated the presence of intrauterine infection earlier than WBC or ESR.