May 19, 2008 by Misha Safranski
As a confirmed birth junkie, I have heard over and over again birth stories where the baby was born by cesarean for either fetal distress or failure to descend, and the difficulties are blamed on "the cord was around the baby's neck". Is this condition - scientifically termed "nuchal
cord" - actually dangerous? A new study backs up previous research showing that nuchal cord is not the threat it's perceived to be.
A study published this year in the Journal of Perinatal Medicine showed there were no statistically significant differences in outcomes of post-term pregnancies involving a nuchal cord verses no nuchal cord. Drs. Ghosh and Gudmundsson performed color ultrasound on 202 women with post-term pregnancies. Nuchal cords were detected in 69 of the women. There were no significant differences in Apgar scores, umbilical cord anomalies, cesarean section, perinatal death or admission of the baby to the NICU (neonatal intensive care unit).
These findings confirm what has been found in most of the past research on nuchal cord outcomes. A 2006 study from the Archives of Obstetrics and Gynecology was on a much larger scale, looking at the outcomes of 166,318 deliveries during a 15 year study period, 24,392 of which had a documented nuchal cord at birth. The authors, Sheiner et. Al, conclude: "Nuchal cord is not associated with adverse perinatal outcome. Thus, labor induction in such cases is probably unnecessary."
The interesting thing about the Sheiner study is that despite the equivalent outcomes among nuchal cord babies and those without the cord wrapped around the neck, there were higher rates of labor induction and non-reassuring fetal heart tones during labor among the nuchal cord cases.
These two factors are most likely related. We know without a doubt that induction of labor can cause fetal distress. The fact that there were higher induction rates in the nuchal cord group could very well explain the higher rate of transient fetal distress. Induction is nearly always accompanied by AROM (artificial rupture of membranes), which can cause undue pressure on the cord, which can in turn result in blips in the hearttones. Regardless of the cause, the outcomes were still good.
Finally, we look at yet another study which demonstrated that nuchal cord does not result in worse outcomes. In a 2005 study looking at the effects of nuchal cord on birthweight and immediate neonatal outcomes, Mastrobattista, et. Al examined the outcomes of 4426 babies, 775 of whom had a nuchal cord. They found that there were no significant differences between the two groups in birthweight, non-reassuring fetal hearttones, Apgar scores below 7, or operative vaginal deliveries. The cesarean rate was actually highest among the women whose babies did not have a nuchal cord.
The most important thing to keep in mind is that unborn babies do not breathe through their mouth and neck - they receive oxygen through the umbilical cord. This is why it normally doesn't matter if the cord is around the neck (unless the cord is being compressed too much, which is fairly rare). The baby cannot "choke to death" before she/he is born. What we can conclude from the overwhelming majority of data is that nuchal cord - or "cord around the neck" - is not pathological; that is to say, it's not an abnormality. It is a normal condition of the umbilical cord and typically causes no problems with the delivery, even though doctors frequently try to convince parents otherwise.
References:
J Perinat Med. 2008;36(2):142-4. Nuchal cord in post-term pregnancy - relationship to suspected intrapartum fetal distress indicating operative intervention. Ghosh GS, Gudmundsson S. Department of Obstetrics and Gynecology, Malmö University Hospital, Malmö, Sweden.
Arch Gynecol Obstet. 2006 May;274(2):81-3. Epub 2005 Dec 23. Nuchal cord is not associated with adverse perinatal outcome. Sheiner E, Abramowicz JS, Levy A, Silberstein T, Mazor M, Hershkovitz R. Department of Obstetrics and Gynecology, Soroka University Medical Center, Ben Gurion University of the Negev, Beer-Sheva, Israel. sheiner@bgu.ac.il
1 comment:
Thank you for such an insightful explanation. I've had my doubts about the problems caused by the cord being wrapped around the neck in utero (my own baby, born safely at home, had his cord wrapped around his neck three times at birth, with no adverse effects). The distinction between the wrapping and the COMPRESSING is spot on, IMO.
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