胎儿脐带绕颈动态监测

目的 观察脐带绕颈在孕期中的自然变化。方法 收集整个孕期均于我院完成规定的超声检查并分娩的孕妇,最终纳入8016胎,根据超声诊断脐带绕颈情况分为脐带绕颈组与无绕颈组。评估脐带绕颈的发生与脐带长度、羊水量及胎儿预后的相关性。结果 超声检出脐带绕颈5091胎(5091/8016,63.51%);其中脐带绕颈自然复位2680胎(2680/5091,52.64%)。晚孕期持续脐带绕颈者分娩后绕颈变化率最低(329/1294,25.43%)。脐带绕颈组脐带长度为(53.98±7.70)cm,无脐带绕颈组(51.34±6.20)cm,二者差异有统计学意义(t=15.32,P<0.001)。与羊水量正常、羊水量少相比,羊水量多时,脐带绕颈发生率最高(136/187,72.73%,P<0.05),脐带绕颈与脐带长度、羊水量均呈正相关(P<0.05)。剖宫产及经阴道分娩者中,是否发生脐带绕颈胎儿出生后的Apgar评分差异均无统计学意义(P均>0.05)。脐带绕颈组剖宫产率高于无绕颈组(χ²=10.23,P<0.05)。结论 脐带绕颈多集中发生于中晚孕期,与脐带长度、羊水量具有一定的相关性。     

Assessment of umbilical cord coiling during the routine fetal sonographic anatomic survey in the second trimester.

OBJECTIVE: The purpose of this study was to evaluate the sonographic accuracy to determine the umbilical coiling index (UCI) during the routine fetal anatomic survey in the second trimester. METHODS: In 300 consecutive women with singleton pregnancies and absence of gross fetal anomalies who had a routine second-trimester fetal anatomic survey, a distance between 2 pairs of coils was measured from the longitudinal images of the umbilical cord, and the antenatal UCI (aUCI) was calculated. The aUCI was compared with true UCI results obtained after birth. RESULTS: Two hundred thirty-six patients had adequate sonographic umbilical cord images, and all required demographic, antenatal, and labor data collection to meet the inclusion criteria. A statistically significant correlation between aUCI and true UCI was found (P < .0001; r = 0.643). The mean aUCI was 0.402 (80% confidence interval, 0.382), and the true UCI at birth was 0.203 (80% confidence interval, 0.176). The sonographic evaluation showed 12.3% and 8.9% of hypocoiled and hypercoiled cords, whereas evaluation at birth found 10.6% and 8.1% hypocoiled and hypercoiled umbilical cords, respectively. The sensitivity values of sonography to predict hypocoiling and hypercoiling at birth were 78.9% and 25.4%, respectively. CONCLUSIONS: A sonographic evaluation of umbilical cord coiling in the second trimester correlates with the true UCI at birth, although the sensitivity in predicting coiling patterns as hypocoiled and hypercoiled cords is less accurate. A difference between the aUCI and matched UCI at birth could be explained by a sonographic error in the sampling of different umbilical cord segments with discordant coiling patterns or the possibility of a dynamically evolving UCI with advancing gestational age.     

Sonographic evaluation of umbilical cord insertion with umbilical coiling index.

PURPOSE: The aim of this study was to investigate the association between umbilical cord hypocoiling and abnormal placental insertion of the umbilical cord. METHODS: Umbilical coiling was measured by sonography in 253 pregnant women in their second or third trimester. An umbilical coiling index, defined here as the reciprocal of the length of 1 umbilical vascular coil, of less than 0.1 was considered hypocoiled. The distance from the placental edge to the insertion of the umbilical cord was measured after delivery, and the results were used to classify cord insertion as normal, marginal, or velamentous. RESULTS: Cord insertion was abnormal in 66.7% of the fetuses with umbilical hypocoiling but in only 1.3% of those whose coiling index was > or = 0.1 (p < 0.05). CONCLUSIONS: Hypocoiling of the umbilical cord was highly associated with abnormal cord insertion. The presence of a hypocoiled umbilical cord may indicate the presence of abnormal cord insertion and thus may be useful for obstetric management.     

彩超评估脐带旋转指数与脐带异常附着的相关性研究

目的：观察脐带旋转指数异常与脐带附着异常是否相关。方法：超声检测350例孕晚期胎儿的脐带旋转指数（1／A）。该指数为脐动脉围绕脐静脉旋转1个周期后占脐静脉的长度的倒数,指数小于0．1考虑为少旋转。分娩后测量脐带附着点到胎盘边缘的距离,将结果分为正常附着、边缘性附着和帆状附着。结果：少旋转组的胎儿脐带约有76．5％为异常附着,正常旋转或高旋转约有2．2％的脐带异常附着,胎儿脐带旋转指数与脐带附着点到胎盘边缘距离之间的相关系数为r=0．953。结论：脐带少旋转与脐带异常附着有显著相关性,若存在脐带少旋转则可提示存在脐带异常附着。     

Impact of nuchal cord on measurement of fetal nuchal translucency thickness.

OBJECTIVE: To define the impact of nuchal cord on the measurement of fetal nuchal translucency thickness (NT). METHODS: Between December 2004 and June 2006, we examined prospectively 53 fetuses that were observed on routine first-trimester ultrasound examination between 11 + 3 and 13 + 6 weeks of gestation to have nuchal cord causing an indentation in the skin in the nuchal region. The fetuses were re-examined after a median interval of 132 min, when the cord was no longer around the neck and indentation of the skin had resolved. Various NT measurements (highest, lowest, mean) with the cord located around the neck (nuchal cord) were compared with NT measurements in the absence of nuchal cord ('true' NT) in the same fetuses. Measurements were considered to be equal when they were within mean +/- 1.96 SD, defined by our own intraobserver repeatability according to the method of Bland and Altman. RESULTS: The mean of the largest and the smallest of six measurements in the presence of nuchal cord fell within the mean +/- 1.96 SD of our own intraobserver repeatability, i.e. gave a correct estimate of the true NT, in 80% of fetuses, while the NT was overestimated in 10% and underestimated in 10% of fetuses. The largest and the smallest of six measurements in the presence of nuchal cord gave an underestimate of the true NT in 2% of fetuses and an overestimate in 4% of fetuses, respectively. CONCLUSION: There is a wide scattering of measurements in fetuses with nuchal cord in comparison to the same fetuses in the absence of nuchal cord. This prevents accurate prediction of the true NT, although the largest and smallest of repeat measurements with nuchal cord can allow calculation of the highest and lowest possible risks, respectively. These facts must be taken into consideration in counseling patients.     

Prenatal color Doppler sonographic evaluation of nuchal encirclement by the umbilical cord

PURPOSE: The aim of this study was to assess whether Doppler flow velocimetry of the fetal middle cerebral and umbilical arteries is affected by nuchal encirclement by the umbilical cord (nuchal cord) in the prenatal period. PATIENTS AND METHODS: The position of the fetal umbilical cord was assessed on color Doppler sonography in pregnant women who were referred to our radiology department between September 14, 1998, and January 14, 2000. Pulsatility and resistance indices and the ratio of peak systolic blood flow velocity to diastolic velocity of the umbilical arteries and middle cerebral arteries of all fetuses were prospectively obtained with Doppler flow velocimetry. The fetuses were categorized into 2 groups: group 1 consisted of fetuses without sonographic evidence of nuchal cord and group 2 of fetuses with sonographic evidence of nuchal cord. The results were statistically analyzed with independent-groups t test. A p value of less than 0.05 was considered significant. RESULTS: During the study period, 230 pregnant women underwent sonographic examination of the fetus, and 68 fetuses were delivered. The sonographic examinations were performed at 24-41 weeks' menstrual age. Of the 46 fetuses in group 1, 1 fetus had nuchal cord at delivery; of the 22 fetuses in group 2, 4 did not have nuchal cord at delivery. The sensitivity of color Doppler sonography in detecting nuchal cord was 95% (18 of 19 fetuses), the specificity was 92% (45 of 49), the negative predictive value was 98% (45 of 46), and the positive predictive value was 82% (18 of 22). No statistically significant differences in middle cerebral artery or umbilical artery Doppler flow velocimetry values were detected between the 2 groups. CONCLUSIONS: Color Doppler sonography is a sensitive and specific method of diagnosing nuchal cord, but fetal middle cerebral artery and umbilical artery Doppler flow velocimetry values are not affected by the presence of nuchal cord in the prenatal period.     

Absence of a relationship between umbilical cord thickness and coiling patterns.

OBJECTIVE: The purpose of this study was to evaluate a relationship between the umbilical cord thickness and cord coiling patterns during the fetal sonographic anatomic survey in the second trimester of pregnancy. METHODS: This was a prospective study of 470 patients with singleton pregnancies who had a fetal anatomic survey with recorded umbilical coiling patterns between 18 and 23 weeks' gestation. The umbilical cord thickness was assessed as an umbilical diameter at the level of the fetal abdominal cord insertion and compared with the antenatal umbilical coiling index (aUCI), calculated as a reciprocal value of the distance between a pair of umbilical cord coils. RESULTS: Three hundred twenty-one patients had adequate sonographic umbilical cord images and maternal demographic, antenatal, and labor data to meet inclusion criteria. The mean aUCI was 0.41 with 10th and 90th percentiles of 0.21 and 0.60, respectively. A total of 10.6% (34/321) and 9.3% (30/321) of patients were categorized as having hypocoiled and hypercoiled umbilical cords, respectively. The mean cord diameter +/- SD was 9.48 +/- 0.97 mm (range 7.0-12.5 mm). There was no statistically significant correlation between aUCI and umbilical cord thickness (P = .1164). CONCLUSIONS: An aUCI, or umbilical coiling pattern, does not correlate with umbilical cord thickness. It appears that a lesser amount of the umbilical supportive tissue, mainly Wharton jelly, is not related to an increased umbilical cord coiling pattern.     

Ultrasonic diagnosis of nuchal encirclement by the umbilical cord: A case and methodological report

A method for the diagnosis of nuchal coiling of the umbilical cord before labor using a combination of real-time and Doppler ultrasonic equipment is presented in this case report. The applicability of the method is discussed. Further evaluation in routine obstetric practice is still required.     

胎儿脐静脉移植材料的应力松弛特性

背景：人脐静脉是动脉移植物的良好替代材料,在移植时除了考虑脐静脉与宿主动脉相匹配外,还应注意其顺应性. 目的：检测胎儿脐静脉近胎盘段和远胎盘段试样的应力松弛特性. 方法：取22-28岁、胎龄38-40周、自然分娩产妇的正常胎儿脐静脉近胎盘段和远胎盘段各10个试样,在电子万能实验机上进行应力松弛实验,在（36.5±0.5）℃的温度场下,以0.1%/s 的应变增加速度对试样施加应变,设定时间为7200 s.采集100个数据,采用归一化分析的方法计算两组试样的归一化应力松弛方程. 结果与结论：脐静脉近胎盘段组7200 s应力下降了0.275 MPa,脐静脉远胎盘段组7200 s应力下降了0.203 MPa,两组7200 s应力下降量差异有显著性意义（P〈0.05）.两组试样应力松弛曲线是以对数关系变化的,并且胎儿脐静脉近胎盘段和远胎盘段具有不同的应力松弛特性.     

超声诊断胎儿脐带绕颈的影响因素及其对策

对９６０例孕妇作产前超声检查,并与分娩结果进行对照分析。认为超声较难确定脐带绕颈３周以上的绕颈圈数,而孕周的大小、超声检查距分娩时间的长短,胎儿的位置都可影响超声诊断胎儿脐带绕颈的准确性。并提出解决方法。     

超声评价脐带螺旋异常与不良围生结局的研究进展

脐带的发展对胎儿的健康和生存至关重要。近年来,临床医师已注意到脐带螺旋异常与多种不良围生结局相关,产前超声检查对诊断脐带螺旋异常有重要意义。本文就脐带螺旋的发生及判断、螺旋异常对妊娠和围生结局的影响、超声评价螺旋异常的价值做一综述。     

Second-trimester ultrasonographic assessment of the umbilical coiling index.

OBJECTIVE: To determine the relationship between gestational age and the ultrasonic measurement of umbilical coiling index (UCI), and to assess the ability of second-trimester ultrasonic measurements of UCI to predict the true UCI, determined at birth. SUBJECTS/METHODS: Five hundred and thirty-one consecutive women with uncomplicated pregnancies, booking for delivery with a singleton pregnancy, were recruited during a routine second-trimester fetal morphology scan. Multiple ultrasonographic measurements of the intercoil distance were performed between two to three coils of the umbilical cord, along its entire visible length. Three hundred and seventy-four patients (70%) were followed until delivery when the true UCI was measured. RESULTS: An adequate portion of umbilical cord for assessment of coiling was visualized in 99% of cases. Adequate ultrasonographic visibility rates for the fetal, middle and placental regions of the cord were different. All three regions of the umbilical cord could only be visualized adequately in 10% of cases, and two regions were visible in 75%. The UCI progressively decreased along the cord from the fetal insertion to the placental insertion. The mean decrease in UCI with increasing gestational age was similar in all parts of the cord before the 23rd week (160 days) of pregnancy, and plateaued off after this point, except in measurements performed near the fetal insertion. The sensitivity of second-trimester ultrasound examination for predicting hypercoiling at birth was 17.3% and for predicting hypocoiling was 9.1%. DISCUSSION: Whilst UCI can be measured easily and reliably in the second trimester these estimates do not accurately reflect the UCI at term. Our original assumption that umbilical coiling does not alter after the initial formation of coils in the first trimester is incorrect; mixed patterns occurred in about 25% of cases. These patterns develop during the second and third trimesters, presumably due to snarls in the cord, and influence the final coiling number and therefore the relationship between the two measurements of UCI.     

胎羊间断性脐带闭塞对静脉导管血流动力学的影响

目的 探讨胎羊间断性脐带闭塞后静脉导管血流频谱变化的意义.方法 12只晚孕山羊(7只实验组,5只对照组)于妊娠116～130 d行宫内外科手术,用套囊充气闭合器完全夹闭脐带,每次夹闭90 s,间隔30 min,重复5次.于实验前5 min、每次夹闭后3 min应用彩色多普勒超声检测静脉导管心室收缩期峰值速度(Vmax)DV、静脉导管峡部的内径(DDV)、搏动指数(PIDV)、DV指数(S-a/S)、血流量(QDV).结果实验组夹闭后DDV[(1.99±0.16)～(2.69±0.53)mm,P＜0.05)]、QDV[(70.25±15.47)～(171.47±72.16)ml/min,P＜0.05)]、PIDV[(0.33±0.09)～(0.7±0.2),P＜0.05)]、DV指数[(0.44±0.04)～(0.62±0.11),P＜0.05)]升高;与对照组差异有统计学意义(P＜0.01).实验组DDV、QDV、PIDV、DV指数与血pH呈负相关(r=-0.579,r=-0.681,r=-0.358,r=-0.310,P＜0.01)、与PaO2呈负相关(r=-0.564,r=-0.622,r=-0.435,r=-0.483,P＜0.01)、与血PaCO2呈正相关(r=0.510,r=0.418,r=0.699,r=0.423,P＜0.01).(Vmax)DV与血气指标无明显相关.结论 静脉导管血流频谱可成为预测胎儿宫内缺氧的有效指标.     

Amniotic fluid and the umbilical cord: The fetal milieu and lifeline

Amniotic fluid volume should be routinely assessed in every second and third trimester case. A review of amniotic fluid physiology and techniques for ultrasound evaluation of fluid volume is presented. The causes and significance of oligohydramnios and polyhydramnios are stressed. Umbilical cord abnormalities are often incidently observed at the time of amniotic fluid evaluation. The clinical significance of some common umbilical cord abnormalities such as a two-vessel cord and nuchal cord are discussed. Other, more uncommon entities such as cord mass lesions are also reviewed. Finally, the role of cord Doppler interrogation in determining fetal well-being is discussed.     

脐血瘦素质量浓度与胎儿发育的关系

目的 研究适于胎龄儿(AGA)和小于胎龄儿(SGA)在不同胎儿发育阶段瘦素变化特点及其与胎龄和体质量的相关规律,探讨瘦素分泌与胎儿发育的关系.方法 采用放射免疫法(RIA)测定不同胎龄出生的80例AGA和72倒SGA的脐血疫素质量浓度,分别对两组婴儿的瘦素质量浓度与其出生体质量、胎龄作直线相关分析和偏相关分析或曲线拟合.结果 AGA组瘦素质量浓度(6.24±1.13)μg/L高于SGA组(3.23±0.94)μg/L(P<0.01),同组男女婴之间瘦素质量浓度差异无统计学意义(P>0.05);AGA组婴儿的瘦素与出生体质量呈正相关(r=0.78,P<0.05),而瘦素与胎龄无直线相关关系(P>0.05),但两者呈三次函数(Cubic)的曲线分布规律(R2=0.68,P<0.01);SGA组耍儿的瘦素与出生体质量和胎龄均无直线相关性(P=0.13,0.17),也不呈曲线分布.结论 AGA的脐血瘦素质量浓度表现为体质量依赖性,瘦素随胎儿体质量的增加而增加,但与胎龄不呈直线关系,妊娠34周后瘦素的分泌量明显增多.SGA瘦素与出生体质量和胎龄均无相关性,妊娠34周后不出现瘦素分泌加速可能与宫内发育迟缓有关.