If an ultrasound detects that the umbilical cord is wrapped around the baby's neck, does that mean that there's a higher risk of the baby being stillborn?
"Nuchal cord" is the medical term for the condition in which the umbilical cord is wrapped one or more times around the unborn baby's neck. Though it might sound at first like such a condition would pose a serious risk of choking the baby in the womb, this is not usually the case.
Nuchal cord is a fairly common condition, occurring in up to a third of all deliveries and in two types (A and B). Type A means that the cord is loosely wrapped, and type B means that the cord is more tightly wrapped around the baby's neck. Type A nuchal cords are rarely problematic and usually is managed by the doctor or trained midwife slipping the cord over the baby's neck during delivery to prevent compression. In a few studies, type B nuchal cords appear to cause an increased risk of C-section, but most studies find no significantly increased risk of complications with any type of ultrasound-detected nuchal cord.
In understanding nuchal cords, it helps to keep in mind that unborn babies don't breathe through their mouths in the womb. Oxygen is delivered through the mother's blood via the placenta and umbilical cord, and the cord is constructed in such a way that the normal movements and somersaults of an unborn baby usually won't disrupt blood flow through the cord. During delivery, trained doctors or midwives know to monitor for nuchal cord and take appropriate intervention when needed and thus it is rare that the condition causes any problems.
Sources:
Caesarean section for nuchal cord - query bank. May 2009. Royal College of Obstetricians and Gynaecologists. Accessed: Feb 2010. http://www.rcog.org.uk/womens-health/clinical-guidance/caesarean-section-nuchal-cord-query-bank-may-2009
Collins, Jason H. "Nuchal cord type A and type B." Am J Obstet Gynecol. 1997 Jul;177(1):94.
Fetus or Newborn Problems. Merck Manual Home Edition. Accessed: Feb 2010. http://www.merck.com/mmhe/sec22/ch261/ch261c.html
Mastrobattista JM, Hollier LM, Yeomans ER, Ramin SM, Day MC, Sosa A, Gilstrap LC 3rd. "Effects of nuchal cord on birthweight and immediate neonatal outcomes." Am J Perinatol. 2005 Feb;22(2):83-5.
E. Peregrine, P. O'Brien, E. Jauniaux. "Ultrasound detection of nuchal cord prior to labor induction and the risk of Cesarean section" Ultrasound in Obstetrics and Gynecology. Volume 25 Issue 2, Pages 160 - 164
Sheiner E, Abramowicz JS, Levy A, Silberstein T, Mazor M, Hershkovitz R. "Nuchal cord is not associated with adverse perinatal outcome." Arch Gynecol Obstet. 2006 May;274(2):81-3. Epub 2005 Dec 23.
Umbilical Cord Abnormalities. March of Dimes. Accessed: Feb 2010. http://www.marchofdimes.com/professionals/14332_4546.asp#nuchal
