E Henry; RL Andres; RD Christensen

Disclosures

J Perinatol. 2013;33(3):231-234. 

In This Article

Abstract and Introduction

Abstract

Objective: The best practices for the care of a neonate born after a tight nuchal cord have not been defined. As a step toward this, we compared the outcomes of neonates born after a tight nuchal cord vs those born after a loose nuchal cord vs those born after no nuchal cord.
Study Design: This was a retrospective comparison using electronic data of all deliveries during a 6-year period (2005 to 2010) in a multihospital healthcare system in the western United States. At the time of delivery, each birth was recorded as having a tight nuchal cord, a loose nuchal cord or no nuchal cord. Nuchal cord was defined as a loop of umbilical cord ≥360° around the fetal neck. 'Tight' was defined as the inability to manually reduce the loop over the fetal head, and 'loose' as the ability to manually reduce the loop over the head.
Result: Of 219 337 live births in this period, 6.6% had a tight nuchal cord and 21.6% had a loose nuchal cord. Owing to the very large number of subjects, several intergroup differences were statistically significant but all were judged as too small for clinical significance. For instance, those with a tight nuchal cord had a very slightly older gestational age, a very slightly lower birth weight, a preponderance of male fetuses, primagravid women, singleton pregnancies and shoulder dystocia (all P<0.001). Term neonates with a tight nuchal cord were slightly more likely to be admitted to a Neonatal Intensive Care Unit (6.6% vs 5.9% admission rate, P=0.000). Those with a tight nuchal cord were not more likely to have dopamine administered or blood hemoglobin measured on the first day, nor were they more likely to receive a transfusion or to die. The subset of very low birth weight neonates with a tight nuchal cord, compared with those with no nuchal cord, were of the same gestational age and birth weight, with the same Apgar scores, and were not more likely to have severe intraventrucular hemorrhage, retinopathy of prematurity or periventricular leukomalacia, or to die.
Conclusion: The presence of a tight nuchal cord is not uncommon, occurring in 6.6% of over 200 000 consecutive live births in a multihospital health system. No differences in demographics or outcomes, judged as clinically significant, were associated with a tight nuchal cord. Thus, we speculate that the best practices for neonatal care after a tight nuchal cord do not involve an obligation to conduct extra laboratory studies or extra monitoring solely on the basis of the report of a tight nuchal cord.

Introduction

'Nuchal cord' has been defined as a ≥360° wrapping of the umbilical cord around the fetal neck.[1–3] At the time of birth, nuchal cords are sometimes labeled as being either 'tight ' or 'loose' depending on whether the loop can be manually reduced over the fetal head.[2,3] Two reports in the 1980s described hypovolemic shock and anemia in neonates delivered after a tight nuchal cord.[4,5] The proposed mechanism causing shock/anemia was partial cord compression, with impaired fetal blood flow through the umbilical vein, because of its relatively thin wall, but unimpeded arterial flow from the fetus to the placenta. It was proposed that in this way the fetal/placental blood volume becomes reproportioned away from the fetus and into the placenta.[4,5]

Nuchal cords at term are common, with incidence reports ranging from 15 to 34% of births;[1–3,6,7] however, only a small but unreported fraction of these are tight. Moreover, the odds that a tight nuchal cord will result in subsequent neonatal hypovolemia, anemia or other problems are not known. Thus, it is not clear whether clinicians caring for a neonate born after a tight nuchal cord should specifically monitor for certain problems or outcomes.

Following the two reports of hypovolemia and anemia after a tight nuchal cord,[4,5] several studies reported a wide range of findings and outcomes. Published neonatal outcomes have included fetal demise,[8] physiological or neurodevelopmental impairment,[9–13] increased risk of cerebral palsy[13,14] and no clinical problems at all.[15–18] Consequently, interpretations of the significance of a tight nuchal cord at birth vary widely, with opinions ranging from this being a potentially lethal problem for the neonate to it being a normal and benign perinatal occurrence.[15] Collins et al.[3] proposed that studies using very large cohort groups are needed to assess the true risks of a tight nuchal cord. We reasoned that the data resources of Intermountain Healthcare could provide useful insights into this issue. Specifically, in our data marts, information regarding nuchal cord is kept on every delivery, including whether, if present, it was tight or loose. We speculated that by linking that information with the electronic data marts for the neonatal courses any associations between tight nuchal cord and neonatal hypovolemia, anemia or other problems could be evaluated statistically using large sample sizes.

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