Abnormal umbilical cord coiling is associated with adverse perinatal outcomes

The normal umbilical cord coil index is one coil/5 cm, i.e., 0.2 +/- 0.1 co ils completed per cm. We report the frequency and clinical correlations of abnormally coiled cords among 1329 cases referred to our placental patholog y services. Twenty-one percent of cords were overcoiled and 13% were underc oiled. Abnormal cord coiling was seen at all gestational ages. Principal cl inical correlations found in overcoiled cords were fetal demise (37%), feta l intolerance to labor (14%), intrauterine growth retardation (10%), and ch orioamnionitis (10%). For undercoiled cords, the frequencies of these adver se outcomes were 29%, 21%, 15%, and 29%, respectively. Abnormal cord coilin g was associated with thrombosis of chorionic plate vessels, umbilical veno us thrombosis, and cord stenosis. Thus, abnormal cord coiling is a chronic state, established in early gestation, that may have chronic (growth retard ation) and acute (fetal intolerance to labor and fetal demise) effects on f etal wellbeing. The cause of abnormal cord coiling is not known. Its effect s on neurological status of survivors are also unknown. Antenatal detection of abnormal cord coil index by ultrasound could lead to elective delivery of fetuses at risk, thereby reducing the fetal death rate by about one-half . We recommend that the cord coil index become part of the routine placenta l pathology examination.