When I speak to women in their first pregnancies, they usually have no idea what cervical dilation is. But, ask any mom who has gone through labor, and she can tell you it’s very important.
The cervix is the doorway from the womb (uterus) to the birth canal. When a woman is not pregnant, her cervix is firm, long, and closed. During pregnancy, the cervix should stay closed so that the baby can safely grow inside the uterus. When the time finally comes for the baby’s birthday, labor starts.
In the medical literature, the very definition of labor is “contractions that bring about cervical change.”
The dilation does not only help healthcare providers judge whether a woman is in labor and whether it is time to admit her to the hospital, but it also guides decisions throughout the labor course. If the dilation stops changing, a healthcare provider will often recommend interventions to encourage it to dilate more. The most common of these are intentionally breaking the bag of water or giving a drug called oxytocin or pitocin. Oxytocin strengthens contractions, but it is not without risks. Up to 80% of women in labor currently receive oxytocin. If the dilation does not change for several hours despite adequate contractions, providers will recommend a cesarean birth. 18% of all cesarean births in the United States are performed because labor has stopped progressing.
What exactly is happening when providers “check the dilation?”
Currently, we check dilation by feeling for the cervix with two fingers. Since the cervix is at the back of the birth canal, we must use feel and not sight. We place two fingers at opposite sides of the cervical opening and estimate how far apart our fingers feel. As you might imagine, this technique is inaccurate. In trials using simulators, doctors, midwives, and nurses get the correct measurement only about 50% of the time.,, If two expert obstetricians check the same cervix, they only agree on the dilation 49% of the time. This can create uncertainty and confusion, but there are currently no tools in general use to solve this problem.
Cervical dilation is the key metric for diagnosing labor. It tells providers whether it is time to admit a woman to the hospital and whether they should recommend interventions, medications, or even a cesarean birth. The number is inaccurate, often leading to confusion. My life’s work is to create a more accurate way to measure this important number, so I invented a measuring tool called DilaCheck® .
If you have a question about this topic or would like to share your story about how cervical dilation played a role in your labor experience, please email me at email@example.com. I always welcome speaking with new and expecting moms and families, and healthcare practitioners!
This article is for educational purposes only and is not medical advice. Each case is individual, so please consult with your medical care provider.
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Zhang J et al. Contemporary Patterns of Spontaneous Labor with Normal Neonatal Outcomes. Obstet & Gynecol. 2010 Dec; 115(6):1281-1287.Eggebø TM, Wilhelm-Benartzi C, Hassan WA, et al. A model to predict vaginal delivery in nulliparous women based on maternal characteristics and intrapartum ultrasound. Am J Obstet Gynecol. 2015 Sep; 213;362.e1-6.Barber EL, Lundsberg LS, Belanger K, Pettker CM, Funai EF, Illuzzi JL. Indications contributing to the increasing cesarean delivery rate.Obstet Gynecol. 2011 Jul;118(1):29-38.Tuffnel, et al. Simulation of cervical changes in labour: reproducibility of expert assessment. The Lancet. 1989. Nov;1089-1090.Phelps J, Higby K, Smyth M, Ward J, Arredondo F, Mayer A. Accuracy and Intraobserver variability of simulated cervical dilatation measurements. Am J Obstet Gynecol. 1995 Sep;173(3 Pt 1):942-5.Huhn K, Brost B. Accuracy of simulated cervical dilation and effacement measurements among practitioners. Am J Obstet Gynecol. 2004 Nov;191(5):1797-9. Buchmann E, Libhaber E. Accuracy of cervical assessment in the active phase of labour. BJOG. 2007 Jul;114(7):833-7.
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