|Written by Kristi Runyon|
|Monday, 01 November 2010 11:08|
Cervical Insufficiency The cervix is the area that connects the top of the vagina to the bottom of the uterus. It is about one to two inches long. During pregnancy, the cervix remains thick and strong to support the weight of the growing fetus, keeping the baby inside the uterus. As the end of the pregnancy nears (roughly 40 weeks), the cervix begins to soften and thin. The cervical canal widens. At birth, the baby passes through the cervix and into the birth canal for delivery.
In women with cervical insufficiency (also referred to as an incompetent cervix) the cervix unexpectedly starts to dilate long before the baby is ready to be born. The weight of the fetus is too heavy for the thinned cervix to support, causing the baby to slide into the birth canal prematurely. In most cases, the woman won’t have any contractions to warn of the impending delivery.
According to the American Pregnancy Association, cervical insufficiency occurs in about one percent of all pregnancies. Some risk factors for the condition include: previous cervical surgery, cervical damage from a prior birth, trauma from a dilation and curettage (D&C) or previous miscarriage, malformed cervix or uterus or exposure to the drug, diethylstilbestrol (DES).
Arthur Haney, M.D., Reproductive Endocrinologist with the University of Chicago Medical Center in Chicago, IL, says cervical insufficiency is sometimes mistakenly labeled as an early miscarriage. However, a true miscarriage tends to occur much earlier in the pregnancy, causing bleeding, cramping and sometimes, expelling of tissue from the vagina. Women with cervical insufficiency have a normal pregnancy up to about 18 to 20 weeks, then suddenly deliver the fetus. Sometimes these women will have contractions because, as the cervix thins, bacteria can enter the canals and come into contact with the membranes surrounding the fetus. This infection triggers contractions as the uterus tries to expel the infection.
Cerclage for Cervical Insufficiency Women with cervical insufficiency are at risk for future pregnancy loss unless doctors intervene. The most common method of treatment is a procedure called vaginal cerclage. A tiny stitch of woven synthetic material is placed around the cervix to reinforce the structure and prevent it from opening. It's typically done between 13 and 15 weeks of the pregnancy. The stitch is removed between weeks 36 to 38, allowing the baby to be born naturally. However, it can be days to weeks until labor begins.
Haney says vaginal cerclage is effective in preventing pregnancy loss for about 75 to 80 percent of women. One of the main drawbacks of the procedure is that women are often confined to bed rest for the remaining time of their pregnancy. In addition, some still deliver prematurely, leading to long hospital stays in the NICU for the baby.
The Abdominal Approach Another way to perform cerclage is through a small incision in the lower abdomen (called transabdominal cerclage). Haney explains the incision is made above the pubic bone, near the bikini line. The stitch is placed at the top of the cervix, where it can provide more support for the uterus, and permanently remain in place.
One of the biggest advantages of abdominal cerclage is that women who have the procedure don’t require bed rest for the remaining pregnancy. Women stay in the hospital overnight and have no restrictions on activity (other than not being able to drive for one week). The one drawback is that the cervix is unable to open, so the baby must be delivered through cesarean section.
Transabdominal cerclage may be a good alternative for women for whom vaginal cervical cerclage has failed. It may also be appealing to women who want several children and don’t want to have a vaginal cervical cerclage for each pregnancy.
For general information on cerclage or incompetent cervix:
American Pregnancy Association, http://www.americanpregnancy.org
March of Dimes, http://www.marchofdimes.com
Carter, F., et al., “Abdominal Cerclage for the Treatment of Recurrent Cervical Insufficiency,” American Journal of Obstetrics and Gynecology, July 2009, Vol. 20, No. 1, pp. 111.e1-111.e4.
Daskalakis, G., “Prematurity Prevention: The Role of Cerclage,” Current Opinion in Obstetrics and Gynecology, April 2009, Vol. 21, No. 2, pp. 148-152.
Debbs, R., and J. Chen, “Contemporary Use of Cerclage in Pregnancy,” Clinical Obstetrics and Gynecology, December 2009, Vol. 52, No. 4, pp. 597-610.
Lotgering, Frederik, “Clinical Aspects of Cervical Insufficiency,” BMC Pregnancy and Childbirth, June 1, 2007, Vol. 7, Suppl. 1, p. S17.
Woensdregt, Karlijn, M.D., et al., “Effect of 2 Stitches Versus 1 Stitch on the Prevention of Preterm Birth in Women with Singleton Pregnancies Undergoing Cervical Cerclage,” American Journal of Obstetrics and Gynecology, April 2008, Vol. 198, No. 4, pp. 396.e1-396.e7.
Research compiled and edited by Barbara J. Fister
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