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.