What is going on in the body? The normal cervix begins to open after about 9 months of pregnancy. It starts to open only in response to uterine contractions just before birth. But an incompetent cervix begins to open and thin out before contractions have begun and before a pregnancy has reached term. The cause is a weakness in the cervix. The weakened cervix opens because of growing pressure from the uterus as pregnancy progresses.
What are the signs and symptoms of the condition? The main sign of this condition is painless opening of the cervix without labour. It is most common between the third and seventh months of pregnancy. There may be vaginal spotting, or bleeding. The amniotic membrane, or the "bag of waters," then ruptures. This usually causes the loss of the foetus. Without treatment, future pregnancies are likely to be affected as well.
What are the causes and risks of the condition? Factors that increase the likelihood of this condition include:
an abnormally formed cervix or uterus due to a birth defect. This may occur, for example, if a woman's mother took a drug called diethylstilbestrol, or DES, while she was pregnant.
damage to the cervix, such as during a previous birth
What can be done to prevent the condition? If a woman has no history of the condition, it usually cannot be prevented. Once the diagnosis is made, treatment is available for future pregnancies.
How is the condition diagnosed? This condition is diagnosed when the woman begins to have symptoms. A physical examination by the physician will show the cervix beginning to shorten and dilate, or open. A pregnancy ultrasound can show this earlier, as the cervix opens from above down.
What are the long-term effects of the condition? The long-term effects of this condition are premature labour and miscarriage with each pregnancy. The emotional suffering after one or more miscarriages can be severe. Treatment is often successful in allowing full-term pregnancy and normal delivery.
What are the risks to others? This condition is not contagious and poses no risks to others.
What are the treatments for the condition? A cervical cerclage can be placed during future pregnancies to prevent miscarriage in a woman with this condition. A cerclage is a stitch inserted around the cervix to prevent it from opening too early. The procedure is usually done at 14 to 16 weeks of pregnancy. The woman may be put on bed rest for a short period of time. The cerclage can be removed at the time of delivery or left in place if a caesarean section is done.
What are the side effects of the treatments? Side effects are possible with any surgery. These include bleeding, infection, and reactions to the medications used to control pain. The most common possible side effects of a cerclage include:
premature rupture of the membranes, or water breaking
infection of the uterus, foetal membranes, or foetus
What happens after treatment for the condition? After a cerclage is placed, the woman is kept on bed rest for 24 hours. She will be monitored for any uterine contractions, or labour. She will be advised to get plenty of rest each day, and to decrease her physical activity for the remainder of her pregnancy. Vaginal intercourse should be avoided until after delivery. The stitch is most often removed at about 37 weeks or if labour commences.
How is the condition monitored? The woman will need to be followed closely throughout her pregnancy to check on the condition of the cervix. Antenatal visits will be more frequent than usual. The woman should tell her obstetrician right away if she has any contractions or leaking of fluid from the vagina.
Author: Gail Hendrickson, RN, BS Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
