As babies grow in the womb, the weight of the pregnancy increases and exerts more pressure onto the cervix (the womb’s opening to the birth canal). In some women, the cervix is unable to sustain the pressure and may open prematurely. This condition is called cervical Incompetence, and could lead to a preterm delivery or miscarriage in the 2nd or 3rd trimester.
Cervical incompetence is rare and only occurs in about 1% of pregnancies. Often times, gynecologists don’t check for it routinely unless you are at high risk. However, it is one of the most common causes of miscarriages in the 2nd trimester.
Who is at Risk for Cervical Incompetence?
Women who have had previous trauma or surgery to the cervix are at increased risk.
Cervical surgeries can weaken the cervix. Women who have had miscarriages or difficult previous births may also be at high risk. Additionally, certain cervical or uterine birth defects make some women more prone to cervical weakness, as well as women who have been exposed to DES (Diethylstilbestrol).
Cerclage as Treatment for Cervical Incompetence
An OB-GYN can place a cerclage to hold the cervix closed in the event of cervical incompetence. In many cases, this has been effective in delaying labor.
A cerclage is a surgical procedure performed through the vaginal canal. The surgeon stitches the cervix to prevent early dilation.
There are a few different ways that a cerclage can be placed. All of them serve to tighten and strengthen the cervix to keep it closed until the pregnancy is brought to term.
- We can place the stitches around the outside of the cervix.
- We can make a small incision in the cervix, and then thread a surgical tape through it to close it.
If we do not catch the cervical incompetence until later in the pregnancy, the amniotic sac may start to protrude through the cervix. We can address this problem in one of two ways:
- We introduce a catheter (narrow tube) into the cervix, and then inflate a small balloon at the end of the catheter.
- We insert a catheter through the urethra to fill the bladder with liquid. The pressure from the bladder can then nudge the amniotic sac back through the cervix.
- Once the amniotic sac is back in place, we can stitch up the cervix.
The stitches must be taken out prior to the beginning of labor, which is usually done at 36 weeks. It will not cause labor to start. However, if you go into early labor without having the stitches removed, it is a medical emergency and they must be removed immediately. In some scenarios, the baby must be delivered via Cesarean section.
As with any surgery, there are some risks to performing a cervical cerclage. These risks are rare and your medical team will take every precaution to ensure a safe procedure. Some risks include:
- Damage to the cervix
- Hemorrhage (blood loss)
- Preterm labor
- Preterm premature rupture of membranes (PPROM) – this means that the amniotic sac ruptures
- Cervical stenosis (narrowing or hardening of the cervix)
- Tearing in the cervix or uterine tissue, if you go into labor with the stitches still in place
If you have reason to believe you are at risk for cervical incompetence, it’s important that you talk to your gynecologist about your concern. It’s better to catch this issue early so that the necessary steps can be taken to reinforce your cervix. Early treatment with cerclage can significantly reduce your chances of preterm labor and miscarriage.