Some women suffer from what is called cervical incompetence. An incompetent cervix fails to remain closed throughout the pregnancy, which increases the likelihood of premature birth. This is where cervical cerclage comes in.
What is an Incompetent Cervix?
During the final weeks of pregnancy a woman’s cervix undergoes a process known as dilation and effacement. Dilation means of course that the cervix is widening; the term effacement refers to the thinning of cervical tissue. Under normal circumstances this process takes place near the end of the pregnancy term, but an incompetent cervix loses its ability to hold things together, and begins to dilate and efface before the pregnancy reaches term. This premature opening of the cervix puts mother and baby at risk for preterm birth, or even miscarriage.
What is Cervical Cerclage?
A cervical cerclage (which is also called a cervical stitch) is a surgical procedure that is performed in order to treat cervical incompetence. Essentially, the surgeon sews the cervix shut—the cervix is closed with sutures in order to prevent premature labor. These sutures are typically removed when the pregnancy is near term—generally around the 37th week—although they can be removed sooner if necessary.
Generally, your doctor will know whether this procedure is necessary by your 14th week of pregnancy, or around the third month. In some cases, however, a woman doesn’t show any signs of a weak cervix until later in the pregnancy. If a woman needs a cerclage late in her pregnancy, the procedure is known as an emergent cerclage. If an emergent cerclage is needed, chances are future pregnancies will also need a cervical cerclage.
If your doctor determines that this procedure is necessary, your surgeon will perform one of the three types of cervical cerclage:
A McDonald cerclage is the most common of these operations. The surgeon uses a kind of pursestring stitch to sew the cervix shut. A McDonald cerclage is generally performed at around the 14th week of pregnancy, and it is usually removed around week 37.
A Shirodkar cerclage is similar to a McDonald cerclage, except that the sutures are passed through the cervical walls so that they are not exposed. Using forceps, the surgeon pulls the cervix toward him while pulling back the vaginal walls. Small incisions are made at the spot where the cervix meets the vaginal tissue. A needle and tape are then passed through these incisions, tying the cervix shut. This operation is more difficult to perform than a McDonald cerclage, but it is thought to lower the risk of infection (although this has not been proved conclusively).
An abdominal cerclage is generally not done unless the cervix is too short to allow a transabdominal cerclage to be attempted, or if a vaginal cerclage has already been attempted without success. Abdominal cerclage may also be attempted if the cervix is lacerated or scarred. For this operation, an incision is made in the abdomen and the cervix is permanently stitched shut at the site of the passage between the cervix and the lower part of the uterus.
After the procedure is complete, the doctor will probably conduct an ultrasound test in order to make sure that the operation has not adversely affected the fetus—i.e., that blood flow has not inadvertently been affected, and that the amniotic sac is still in its proper position above the cervix. Bed rest is generally recommended for a few days following the operation.
Cervical Cerclage Removal
A vaginal cerclage (i.e., a McDonald or Shirodkar cerclage) is generally removed during the 37th week of pregnancy. A McDonald cerclage can usually be removed without anesthesia in a doctor’s office, but a Shirodkar cerclage will have to be removed with another surgical procedure. In some cases, if a woman plans to have more children in the future, a Shirodkar cerclage may be left in place permanently. There is a chance, however, that doing so can affect a woman’s fertility, so if you find yourself in this position, be sure to discuss the matter thoroughly with your doctor.
Why is Cervical Cerclage Done?
A physician is likely to recommend a cervical cerclage if there is noticeable cervical dilation prior to the 24th week of pregnancy. Certain events and conditions can make a woman more likely to require a cervical cerclage. These include:
- A short cervix
- Damage to cervix from previous pregnancy termination
- A previous cone biopsy or an LEEP procedure
- A history of 2nd trimester miscarriages
- Previous cervical cerclage
- Previous emergent cerclage
- Abnormal cervix before conception
Benefits of Cervical Cerclage
There are numerous benefits associated with this procedure. Cervical cerclage is known to prevent miscarriages or premature labor caused by an incompetent cervix in more than 85 percent of cases.
Risks of Cervical Cerclage
Cervical cerclage does not always prevent preterm labor, and there is a risk of complications, including:
- Cervical laceration
- Cervical infection
- Vaginal bleeding
- Cervical dystocia—an inability of the cervix to dilate properly when the time comes
- Cervical stenosis—permanent narrowing of the cervix
- Rupture of the uterus
- Premature breakage of the amniotic sac
- Premature contractions (unrelated to Braxton Hicks contractions)
- Premature labor—the very thing cervical cerclage is supposed to prevent
When to Call Your Doctor
If you’ve had this procedure done, there are symptoms you should look for in order to detect any problems before they become too serious. These symptoms include:
- Nausea and vomiting
- Water leakage
- Your water breaks
- Vaginal discharge has a foul odor
- Vaginal bleeding
- Lower abdominal or back pain that comes and goes like labor pain