The effect of clinical chorioamnionitis on cord blood gas at term

We sought to determine the effect of clinical chorioamnionitis on cord blood gas values in term pregnancies not complicated by any other disease.

2200 consecutive deliveries were studied. Following exclusion of twins, non-viable malformations and stillbirths, as well as mothers with high-risk pregnancy diseases--i.e. hypertension, diabetes, preterm labor, third-trimester bleeding, IUGR, postdates, oligohydramnios, i.v. drug abused, decreased fetal movement, maternal viral infection, UTI or pneumonia (n = 897)--two groups of patients remained: term pregnancies complicated only by clinical chorioamnionitis (n = 81) and uncomplicated term pregnancies (n = 1246).

Evaluation of mean cord blood gas values revealed a significant difference in pH, PO2, PCO2 and BE values, with the infants of mothers with clinical chorioamnionitis having lower pH values (7.23 +/- 0.07 vs. 7.28 +/- 0.07). However, evaluating the independent effect of chorioamnionitis on arterial cord blood pH (using a logistic regression model) showed that clinical chorioamnionitis, by itself, did not contribute to this change in arterial cord blood pH.

Chorioamnionitis was neither the explanation nor the cause for differences in arterial cord blood pH found between the two groups in our study. In cases of chorioamnionitis, these differences were attributed to other factors, such as length of labor, mode of delivery, method of delivery and presence of meconium.