The effect of umbilical cord coiling ındex measured in antenatal period on pregnancy results

Purpose To evaluate the association between ultrasonographically measured umbilical coiling index (UCI) at 18–24 weeks of gestation and adverse perinatal outcomes in primigravid pregnancies. Methods This prospective study included 461 primigravid women with singleton pregnancies. UCI was measured at 3 cord segments and classified as hypocoiled (< 0.20), normocoiled (0.20–0.40), or hypercoiled (> 0.40) using percentile distribution and ROC-derived thresholds. Maternal characteristics, delivery outcomes, fetal well-being, placental measurements, cord blood gas values, and neonatal outcomes were compared using Kruskal–Wallis, Mann–Whitney U, and chi-square tests (p < 0.05 was significant). Results Of the 461 patients, 72 (15.6%) were hypocoiled, 244 (52.9%) normocoiled, and 145 (31.5%) hypercoiled. No significant differences were found in maternal age, BMI, gestational age at delivery, hypertension, diabetes, or placental abruption. Birth weight was lowest in the hypocoiled group (p < 0.001). Umbilical artery pH was significantly lower in the hypercoiled group (p < 0.001). Both hypo and hypercoiled groups showed significantly reduced placental weight/thickness (p < 0.001) and higher rates of non-reassuring non-stress tests (34.7 and 28.3% vs. 9.0%, p < 0.001). Meconium-stained amniotic fluid (p = 0.003), oligohydramnios (p < 0.001), and intrauterine growth restriction (p < 0.001) were more common in abnormal coiling groups. Five-minute Apgar scores were significantly lower in both abnormal groups (p < 0.001). No association was found with fetal death (p = 0.575). Conclusion Both decreased and excessive umbilical cord coiling in the second trimester are associated with impaired fetal growth and adverse perinatal outcomes. Routine second-trimester UCI assessment may help identify high-risk pregnancies.