THE SIGNIFICANCE OF AN ANTENATAL NUCHAL CORD

本提案的长期目标是评估产前颈索对人类胎儿的潜在短期和长期生理和发育影响。初始资助期的具体目的是确定无症状产前颈带的存在是否具有临床意义，如果有，是否有任何辅助发现对制定治疗计划有潜在价值。要检验的零假设是：(1)颈索的存在是宫内生活中随机的短暂事件；(2)分娩前颈索的存在不会产生胎儿应激或改变短期或长期胎儿结局的证据；(3)特定的解剖结构与6个月至5岁之间的持续或神经发育表现无关；(4)产前颈索胎儿的生物物理和/或生化特征不能预测6个月至5岁之间的神经发育表现。在怀孕18-22周时，将招募330名低风险的孕妇。她们将在妊娠24-26周、30- 32周和36-38周接受非应激测试、生物物理特征、速度测定、常规I级超声检查和彩色多普勒脐带位置测定，研究小组成员将监测妊娠和分娩的临床过程和结果。除非其他测试结果表明胎儿可能存在损害，否则受试者及其医生将对除形态测量结果外的所有结果一无所知。将特别关注临床干预的发生率，以表明胎儿窘迫、是否存在胎粪、胎儿心率模式、胎龄出生体重、出生时脐带、Apgar评分、羊水促红细胞生成素和脐动脉血气。婴儿随访将包括出生后第5天的颅内超声检查，以及6个月、1岁、2岁和5岁时的形态测量和神经发育评估。在实验动物和人类分娩过程中有证据表明，脐带缠绕会减少脐带血流量，导致胎儿心率模式的变化，并可能导致发病率和死亡率。人类胎儿分娩前颈带的发生率似乎与出生时的发生率相当。。问题是辅助发现产前颈索超声检查应引起临床关注。这个建议将提供回答这个问题的数据。

The long range goal of this proposal is to evaluate the potential short- and long-term physiological and developmental effects of an antenatal nuchal cord in the human fetus. The specific aims for the initial funding period are to determine if the presence of an asymptomatic antenatal nuchal cord has clinical significance and, if so, are any ancillary findings of potential value in formulating a management plan. The null hypotheses to be tested are: (1) the presence of a nuchal cord is a random transient event during intrauterine life; (2) the presence of a nuchal cord prior to labor does not produce evidence of fetal stress or alter either short- or long-term fetal outcome:(3) the specific anatomical arrangement is unrelated to either persistence or neurodevelopmental performance between 6 months and 5 years of age; and (4) biophysical and/or biochemical characteristics of fetuses with antenatal nuchal cords are not predictive of neurodevelopmental performance between 6 months and 5 years of age. Three hundred and thirty low risk pregnant women carrying singletons will be recruited at 18-22 weeks gestation. They will undergo a non- stress test, a biophysical profile, velocimetry, a routine level I ultrasound and determination of cord position using color flow Doppler at 24-26, 30- 32 and 36-38 weeks gestation and the clinical course and outcome of the pregnancy and labor will be monitored by a member of the study team. . Both the subject and her physician will be blinded to all but the morphometric findings unless the other test results suggest that fetal compromise may exist. Specific attention will be directed towards the incidence of clinical intervention for the indication of fetal distress, presence or absence of meconium, the fetal heart rate pattern, birth weight for gestational age, nuchal cord at birth, Apgar scores, amniotic fluid erythropoeitin and umbilical artery blood gasses. Infant follow-up will include an intracranial ultrasound on the fifth day of life and morphometric and neurodevelopmental assessments at 6 months, one, two and five years of age. There is evidence in experimental animals and in the human during labor that cord entanglement decreases umbilical blood flow, produces changes in the fetal heart rate pattern and may result in morbidity and mortality. It also appears t the incidence of nuchal cord prior to labor in the human fetus is equivalent to that found at birth. The question is should the ancillary finding of an antenatal nuchal cord on ultrasound exam be a cause for clinical concern. This proposal will provide data that should answer the question.