Non-invasive prediction of intra-amniotic infection and/or inflammation in patients with cervical insufficiency or an asymptomatic short cervix (≤15 mm)

Purpose To identify non-invasive parameters to predict intra-amniotic infection and/or inflammation (IAI) in patients with cervical insufficiency or an asymptomatic short cervix (≤15 mm). Methods This retrospective cohort study included 72 asymptomatic women with cervical insufficiency ( n = 54) or an asymptomatic short cervix ( n = 18) at 17–28 weeks. Maternal blood was collected for the determination of the C-reactive protein (CRP) level and white blood cell (WBC) count, and sonography was performed to measure the cervical length shortly after amniocentesis. Amniotic fluid (AF) was cultured and interleukin-6 (IL-6) level and WBC count were determined. Results The prevalence of intra-amniotic inflammation and a positive AF culture was 22.2 % (16/72) and 8.3 % (6/72), respectively. The best cut-off value for AF IL-6 in predicting the presence of intra-amniotic infection was ≥7.6 ng/mL and was used to diagnose the presence of intra-amniotic inflammation. Women with intra-amniotic inflammation, regardless of culture results, were at increased risk for preterm delivery and adverse outcomes compared to women without intra-amniotic inflammation. In multivariable regression, CRP was the only non-invasive variable statistically significantly associated with IAI. Moreover, the area under the curves for the CRP and AF WBC were not significantly different. Conclusions In women with cervical insufficiency or a short cervix, the risk for IAI can be predicted fairly and non-invasively by measurements of serum CRP. Overall, this non-invasive parameter appears to have similar accuracy to the AF WBC counts for predicting IAI.