Objectives: The diagnostic value of ultrasonographic quantitative indicators of umbilical cord coiling, such as the umbilical coiling index (UCI) and pitch value, in identifying hypercoiling and predicting adverse pregnancy outcomes remains controversial. This study aims to evaluate the predictive value of UCI, pitch value, and the cerebroplacental ratio in pregnancies complicated by umbilical cord hypercoiling.
Methods: Pregnant women with densely coiled umbilical cords identified by routine obstetric ultrasound at Changsha Maternal and Child Health Hospital between November 2022 and November 2024 were enrolled. Complete clinical data, including UCI, pitch value, and cerebroplacental ratio (CPR), were collected. Pregnancy outcome scores were calculated, and newborns were categorized into the normal outcome group (n=177) and adverse outcome group (n=85), with the latter further subdivided into mild (n=51), moderate (n=19), and severe (n=15) subgroups. Differences in baseline data, UCI, pitch value, and incidence of CRP<1 were compared between groups and among subgroups. Correlations between UCI, pitch value, and adverse pregnancy outcomes were analyzed. Receiver operating characteristic (ROC) curve were used to assess the predictive performance of UCI, pitch value, CPR<1, and their combinations.
Results: Compared with the normal outcome group, the adverse outcome group had higher age, parity, parity, incidence of CPR<1, and UCI, while gestational age at delivery and pitch values were lower (all P<0.05). The incidence of obesity, gestational diabetes mellitus, and hypertensive disorders of pregnancy did not differ significantly between the 2 groups (all P>0.05). The normal outcome group showed lower UCI and higher pitch values than all 3 adverse outcome subgroups (all P<0.05), while differences among the 3 adverse subgroups were not significant (all P>0.05). UCI was positively correlated with adverse pregnancy outcomes (rs=0.350, P<0.05), whereas pitch value was negatively correlated (rs=-0.286, P<0.05). ROC curve analysis showed that the area under the curve (AUC) values for predicting adverse outcomes were 0.837 for UCI, 0.886 for pitch value, and 0.610 for CPR<1, with sensitivities of 77.6%, 82.4%, and 27.1% and specificities of 78.5%, 83.6%, and 94.9%, respectively. The combined UCI+CPR<1 and pitch value+CPR<1 models yielded AUCs of 0.841 and 0.886, with sensitivities of 78.8% and 81.2% and specificities of 78.5% and 84.2%, respectively. No significant differences were found between the AUCs of UCI and pitch value (P>0.05), but both outperformed CPR<1 alone (both P<0.001). The combined models showed no significant improvement over UCI or pitch value alone (both P>0.05), though both were superior to CPR<1 alone (both P<0.001).
Conclusions: Most umbilical cord hypercoiling cases had favorable outcomes, with UCI, pitch value, CPR<1 and their combinations demonstrating significant predictive value for adverse pregnancy outcomes.
目的: 超声评价脐带螺旋结构的定量指标脐带螺旋指数(umbilical coiling index，UCI)和螺距值诊断脐带过度螺旋及其是否引起不良妊娠结局存在争议。本研究旨在探讨超声测量脐带过度螺旋定量指标UCI、脐带螺距值及血流动力学指标脑-胎盘率对不良妊娠结局的预测价值。方法: 选取2022年11月至2024年11月在长沙市妇幼保健院行常规产科超声检查观察到脐带螺旋密集的孕妇，收集超声测算UCI、螺距值以及血流动力学指标脑-胎盘率等完整的临床资料，计算妊娠预后评分，根据预后评分将新生儿分为预后正常组(n=177)和预后不良组(n=85)，预后不良组进一步分为预后轻度(n=51)、中度(n=19)和重度(n=15)不良组。比较预后正常组与预后不良组一般情况、临床资料、UCI、螺距值及脑-胎盘率<1发生率的差异，并比较预后正常组与预后不良的3个亚组UCI和螺距值的差异。分析UCI、螺距值与不良妊娠结局的相关性。绘制受试者操作特征(receiver operating characteristic，ROC)曲线，分析UCI、螺距值、脑-胎盘率<1、UCI与脑-胎盘率<1联合及螺距值与脑-胎盘率<1联合预测不良妊娠结局的价值。结果: 预后不良组的年龄大于预后正常组，产次、脑-胎盘率<1发生率和UCI均高于预后正常组，分娩孕周和螺距值均低于预后正常组(均P<0.05);2组肥胖、妊娠糖尿病和妊娠高血压发生率的差异均无统计学意义(均P>0.05)。预后正常组的UCI均低于预后不良的3个亚组，螺距值均高于预后不良的3个亚组(均P<0.05);预后不良的3个亚组组间UCI和螺距值差异均无统计学意义(均P>0.05)。UCI与不良妊娠结局呈正相关(rs=0.350，P<0.05)，螺距值与不良妊娠结局呈负相关(rs=-0.286，P<0.05)。ROC曲线结果显示:UCI、螺距值和脑-胎盘率<1预测不良妊娠结局的曲线下面积(area under the curve，AUC)分别为0.837、0.886和0.610，敏感度分别为77.6%、82.4%和27.1%，特异度分别为78.5%、83.6%和94.9%。UCI与脑-胎盘率<1联合及螺距值与脑-胎盘率<1联合预测的AUC分别为0.841及0.886，敏感度分别为78.8%及81.2%，特异度分别为78.5%及84.2%。UCI和螺距值预测不良妊娠结局AUC的差异均无统计学意义(P>0.05)，但均优于脑-胎盘率<1预测的AUC(均P<0.001)。UCI与脑-胎盘率<1联合及螺距值与脑-胎盘率<1联合预测的AUC与UCI、螺距值单独预测的AUC比较，差异均无统计学意义(均P>0.05)，但均优于脑-胎盘率<1单独预测的AUC(均P<0.001)。结论: 脐带过度螺旋病例大部分预后良好，UCI、螺距值和脑-胎盘率<1及UCI与脑-胎盘率<1联合、螺距值和脑-胎盘率<1联合对不良妊娠结局均有预测价值。.
Keywords: adverse pregnancy outcomes; cerebroplacental ratio; excessive umbilical cord coiling; pitch value; umbilical coiling index.