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Cervical length: Why does it matter during pregnancy?
By Mayo Clinic staffOriginal Article: http://www.mayoclinic.com/health/cervical-length/AN02171
- With Mayo Clinic obstetrician and medical editor-in-chief
Roger W. Harms, M.D.
read biographyclose windowBiography of
Roger W. Harms, M.D.
Roger W. Harms, M.D.
"Nothing helps people stay healthy more than the power of real knowledge about health." — Dr. Roger Harms
As medical director of content, Dr. Roger Harms is excited about the potential for Mayo Clinic's health information site to help educate people about their health and provide them the tools and information to live healthier lives.
The Auburn, Neb., native has been with Mayo Clinic since 1981 and is board certified in obstetrics and gynecology. Dr. Harms is a practicing physician and associate professor of obstetrics and gynecology, and his specialty areas include office gynecology, high-risk obstetrics and obstetrical ultrasound.
From 2002 to 2007, Dr. Harms was director for education at Mayo Clinic, Rochester, Minn. Dr. Harms was the 1988 Mayo Medical School Teacher of the Year and served as associate dean for student affairs and academic affairs. He is the co-author of the "Mayo Clinic Model of Education." In 2008, Dr. Harms was presented the Distinguished Educator Award, Mayo Clinic, Rochester.
Dr. Harms is vice chair of the Department of Obstetrics & Gynecology and medical editor of the Pregnancy section on this website. In addition, Dr. Harms is editor-in-chief of the "Mayo Clinic Guide to a Healthy Pregnancy" book, a month-by-month guide to everything a woman needs to know about having a baby.
"My medical education experience has grown out of a love of teaching, and that is what this site is about," Dr. Harms says. "If any visitor to this site makes a more informed and thus more comfortable decision about his or her health because of the information we provide, we are successful."
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Question
Cervical length: Why does it matter during pregnancy?
During pregnancy, what's the significance of cervical length?
Answer
from Roger W. Harms, M.D.
Cervical length during pregnancy is sometimes associated with preterm labor — labor that begins before week 37 of pregnancy. If you have a short cervix, you might be at increased risk of preterm labor and premature birth. The earlier premature birth happens, the greater the health risks for your baby.
Before pregnancy, your cervix — the lower part of the uterus that connects to the vagina — is normally closed and rigid. During pregnancy, your cervix will gradually soften, decrease in length (efface) and open (dilate) as your baby grows and you prepare to give birth. If your cervix begins to open too soon, you could give birth prematurely.
Various factors can influence cervical length during pregnancy, including:
- Biological differences between women
- Unknown uterine activity
- A uterus that's stretched too far (overdistended)
- Complications caused by bleeding during pregnancy
- Infection
- Inflammation
- Incompetent cervix — a condition that occurs when weak cervical tissue causes or contributes to premature birth or the loss of an otherwise healthy pregnancy
If you experience signs and symptoms of preterm labor — such as regular or frequent contractions, a constant low, dull backache, vaginal spotting, or pelvic pressure — your health care provider might do a pelvic exam to determine if your cervix has begun to open. He or she might also do an ultrasound to measure your cervical length.
If you're in preterm labor, your health care provider will explain possible treatments and the risks and benefits of trying to stop your labor.
If you're not in active preterm labor but meet certain criteria — you're less than 24 weeks pregnant, you have a history of premature birth and an ultrasound shows that your cervix is opening — your health care provider might suggest cervical cerclage. During this procedure, the cervix is stitched closed with strong sutures.
Limited research also suggests that treatment with a form of the hormone progesterone or placement of a silicone device (pessary) around the cervix might decrease the risk of premature birth in women who have short cervixes.
If you're concerned about your cervical length during pregnancy, consult your health care provider. He or she can answer your questions and help you understand how to promote a healthy pregnancy.
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- Goya M, et al. Cervical pessary in pregnant women with a short cervix (PECEP): An open-label randomised controlled trial. The Lancet. In press. Accessed April 20, 2012.
- Caritis SN, et al. Cervical pessary use and preterm birth: How little we know. The Lancet. In press. Accessed April 20, 2012.
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