Definition:
In medicine, cervical incompetence is a condition in which a pregnant woman‘s cervix begins to dilate (widen) and efface (thin) before her pregnancy has reached term. Cervical incompetence is a cause of miscarriage and preterm birth in the second and third trimesters.
In a woman with cervical incompetence, dilation and effacement of the cervix occur without pain or uterine contractions. Instead of happening in response to uterine contractions, as in normal pregnancy, these events occur because of weakness of the cervix, which opens under the growing pressure of the uterus as pregnancy progresses. If the changes are not halted, rupture of the membranes and birth of a premature baby can result.
Sometimes premature effacement (shortening of the vaginal portion of the cervix and thinning of the walls) and dilation of the cervix is not caused by labor, but rather by structural weakness in the cervix itself. This is called cervical incompetence.
The weakness can result from a number of conditions, most due to prior injury to the cervix or resulting from an inherited physical condition of the cervix.
Description of Cervical Incompetence:
When the cervix is damaged, it cannot hold the weight of the pregnancy. The cervix dilates without contractions or pain, sometimes opening completely. The dilation results in the amniotic membranes bulging through the opening and eventually rupturing, often before the baby can survive outside of the uterus. This irritates the uterus and brings on pre-term labor. In many cases, labor is detected when it is too far advanced to stop the process.
Click for Pictures of ultrasonographic findings: at 19th week of pregnancy
The cervix normally stays closed until labor begins. however, if the cervix has been weakened, a condition known as cervical incompetence, the weight of the growing fetus and its surrounding amniotic fluid may cause the cervix to open early, resulting in a miscarriage. cervical incompetence is the cause of about 1 in 4 miscarriages after the 14th week of pregnancy.
Causes:
The cervix may be weakened by previous surgery, such as a cone biopsy, or by any procedure that involves artificial opening of the cervix. for example, a woman who ahs had more than three terminations of pregnancy at an early stage is more likely to develop cervical incompetence.
Symptoms :
Often there are no symptoms of cervical incompetence before miscarriage occurs. at this stage, the mother may feel pressure in the lower abdomen or a “lump†in the vagina.
Women with incompetent cervix typically present with “silent” cervical dilation (i.e., with minimal uterine contractions) between 16 and 28 weeks of gestation. They present with significant cervical dilation (2 cm or more) and minimal symptoms. When the cervix reaches 4 cm or more, active uterine contractions or rupture of membranes may occur.
Diagnosis:
Diagnosis is made by medical history, physical exam, and ultrasound study. A pregnancy test will also be performed.
What might be done?
If you have had a previous miscarriage after the 14th week of pregnancy, your doctor will probably suggest that you have ultrasound scanning to look for evidence of cervical incompetence. The scan is performed through the vagina to measure the thickness of the cervix and may be carried out at an early stage in your next pregnancy or, if possible, when you are planning a pregnancy. If you are at high risk of cervical incompetence, possibly because of previous surgery on the cervix, you may also be investigated for cervical incompetence before or early in pregnancy.
Treatment :
Once the problem of incompetence is diagnosed, the condition may be treatable through a surgical procedure called cerclage (stitching the cervix closed). One or more stitches are placed around or through the cervix to keep it tightly closed.
This is usually performed after the twelfth week of pregnancy, the time after which a woman is least likely to miscarry for other reasons – but it is not done if there is rupture of the membranes or infection.
After surgery, the mother is carefully monitored to check for infection and contractions, which are sometimes brought on by the procedure. After hospital discharge, the patient may remain on bedrest in order to remove any pressure on the cervix and increase the chance of retaining the pregnancy until the baby is viable. The cerclage is usually removed just before childbirth so that the patient can give birth vaginally. In some cases, the cerclage may be left in place, and the baby is then delivered by cesarean section.
Risk Factors:
Risk factors for an incompetent cervix are: a history of incompetent cervix with a previous pregnancy, surgery, cervical injury, DES (diethylstilbestrol) exposure, and anatomic abnormalities of the cervix. A prior D&C can, for example, damage the cervix.
Other causes of cervical weakness include cervical cautery (to remove growths or stop bleeding) and cone biopsy (removal of a cone-shaped section of tissue for study to detect possible precancerous growth). Prior to pregnancy or during the first trimester, there is usually no method to determine whether the cervix will eventually be incompetent.
If the cervix is weak, a stitch can be inserted in it to hold it closed. the procedure is usually done under general or epidural anesthesia between week 12 and week 16 of pregnancy. the stitch will be removed at 37 weeks, before the beginning of the labor. If labor starts while the stitch is still in place, it will be removed immediately to prevent the cervix from
becoming torn. If the stitch fails to prevent a miscarriage, another pregnancy may be successful if a stitch is inserted higher in the cervix.
Cervical incompetence is likely to be a problem in subsequent pregnancies. The cervix may need to be stitches each time to prevent miscarriage.
Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.
Resources:
http://www.healthscout.com/ency/68/361/main.html
http://www.charak.com/DiseasePage.asp?thx=1&id=285
http://en.wikipedia.org/wiki/Cervical_incompetence
http://pennhealth.com/health_info/pregnancy/000194.htm