Before pregnancy, the cervix is closed and rigid. During pregnancy, the cervix gradually softens, decreases in length (effaces) and opens (dilates) in preparation for birth. If you have an incompetent or weak cervix, however, your cervix might begin to open too soon. As a result, you could give birth prematurely.
Your health care provider might recommend cervical cerclage during pregnancy to prevent premature birth if you have:
- A history of three second-trimester miscarriages or premature births or two second-trimester miscarriages with no other identifiable causes
- A short cervix — as shown by ultrasound before week 24 of pregnancy — particularly if you've had a cervical injury, a history of premature birth or multiple miscarriages during your second trimester, or the length of your cervix is rapidly decreasing despite treatment with preventive medications
- Cervical dilation with a visible amniotic sac before week 24 of pregnancy (emergency or rescue cerclage)
If you experience recurrent pregnancy losses despite treatment with preventive medications or cervical cerclage, your health care provider might recommend cervical cerclage before conception. It's possible, however, that the cerclage might reduce your fertility.
Cervical cerclage isn't appropriate for everyone at risk of premature birth. Your health care provider might discourage cervical cerclage if you have:
- Vaginal bleeding
- Preterm labor
- An intrauterine infection
- Premature rupture of membranes — when the fluid-filled membrane that surrounds and cushions the baby during pregnancy (amniotic sac) leaks or breaks before labor begins
- Prolapsed fetal membranes — a condition in which the amniotic sac protrudes through the opening of the cervix
- A multiple pregnancy
- A significant risk of miscarriage due to a severe fetal abnormality
Risks associated with cervical cerclage include:
- Uterine contractions
- Vaginal bleeding
- A tear in the cervix (cervical laceration)
- Inability of the cervix to shorten or open (cervical dystocia)
- Permanent narrowing or closure of the cervix (cervical stenosis)
- An abnormal connection between the bladder and vagina (vesicovaginal fistula)
- Uterine rupture
- Preterm premature rupture of the membranes — when the fluid-filled membrane that surrounds and cushions the baby during pregnancy (amniotic sac) leaks or breaks before labor begins and before week 37 of pregnancy
- Movement of or loosening of the sutures (suture migration)
- Preterm labor
After receiving a cervical cerclage, contact your health care provider immediately if you have leakage of fluid from your vagina, a sign of preterm premature rupture of membranes. Your health care provider might recommend removing the cervical cerclage before week 37 of pregnancy if you have preterm premature rupture of membranes and a uterine infection.
Before cervical cerclage, your health care provider will likely do an ultrasound to check your baby's vital signs and rule out any major birth defects. Your health care provider might also take a swab of your cervical secretions or do amniocentesis — a procedure in which a sample of amniotic fluid is removed from the uterus — to check for infection. If you have an infection that requires antibiotics, ideally you'll complete treatment before the cerclage is done. If your cervix has already begun to open or an ultrasound shows that your cervix is short, however, your health care provider might give you antibiotics shortly before the procedure to reduce the risk of infection. Also, your health care provider might recommend avoiding sex for at least one week before the procedure.
Ideally, an elective cervical cerclage is done between weeks 12 and 16 of pregnancy. An emergency or rescue cerclage, however, can be done up until week 24 of pregnancy if a pelvic exam or ultrasound shows that your cervix is beginning to open. Cervical cerclage is typically avoided after week 24 of pregnancy due to the risk of rupturing the amniotic sac and triggering premature birth. In some cases, cervical cerclage can be done before pregnancy.
If you have prolapsed fetal membranes — a condition in which the amniotic sac protrudes through the opening of the cervix — and your health care provider recommends cervical cerclage, he or she will treat the condition before doing the procedure. Your health care provider might place a thin tube (catheter) in your urethra to fill your bladder and reposition the amniotic sac. Alternatively, your health care provider might insert a balloon-tipped catheter beyond the opening of your cervix and inflate the bulb to push the amniotic sac back into place.
Cervical cerclage is typically done as an outpatient procedure at a hospital or surgery center under regional or general anesthesia. Most cervical cerclage procedures are done through the vagina. Cervical cerclage might be done through the abdomen if transvaginal cerclage is unsuccessful or anatomically difficult due to an extremely short, lacerated or scarred cervix.
During the procedure
During transvaginal cervical cerclage, your health care provider will insert a speculum into your vagina and grasp your cervix with ring forceps. He or she might use ultrasound for guidance during the procedure. Your health care provider will likely use a technique known as the McDonald cerclage or the Shirodkar cerclage. Research suggests no significant difference in outcomes between the two methods.
To place the McDonald cerclage, your health care provider will likely use a needle to place stitches around the outside of your cervix. Next, he or she will tightly tie the ends of the sutures to close your cervix.
In the Shirodkar method, your health care provider will use ring forceps to pull your cervix toward him or her while pulling back the side walls of your vagina. Next, he or she will make small incisions in your cervix where your cervix meets your vaginal tissue. Then, he or she will pass a needle with tape through the incisions and tightly tie your cervix closed. After this method, your health care provider might use fine sutures to reposition vaginal tissue affected by the incisions. If a single cerclage doesn't provide enough closure, your health care provider might place a second cerclage around your cervix.
During transabdominal cervical cerclage, your health care provider will make an incision in your abdomen. He or she might gently elevate your uterus to gain better access to your cervix. Next, your health care provider will use a needle to place tape around the narrow passage connecting the lower part of your uterus to your cervix and tightly tie your cervix closed. Then he or she will settle your uterus back into place and close the incision.
After the procedure
After cervical cerclage, your health care provider will likely do an ultrasound to check your baby's well-being. If you had a transabdominal cervical cerclage, he or she will likely check to make sure blood flow through the uterus wasn't affected by the procedure and that the amniotic sac is positioned above the cerclage. You might experience spotting, cramps and painful urination for a few days. Acetaminophen is recommended for pain or discomfort. If your health care provider used fine sutures to reposition vaginal tissue affected by incisions in your cervix, you might notice passage of the suture material in two to three weeks as the stitches dissolve.
If you had cervical cerclage based on your past history of miscarriages or premature births, you'll be able to go home after you recover from the anesthetic. As a precaution, your health care provider might recommend remaining on bed rest for two days and avoiding sex for at least one week and, afterward, using condoms during sex.
If you had cervical cerclage because your cervix had already begun to open or an ultrasound showed that your cervix is short, your health care provider might prescribe antibiotics to reduce the risk of infection. As a precaution, your health care provider might recommend limiting physical activity and sex until the end of your pregnancy — generally week 32 through week 34 of pregnancy. Your health care provider might also recommend bed rest, although it isn't a proven remedy for preventing premature birth.
Your health care provider might recommend weekly or biweekly visits to examine your cervix until you give birth.
Cervical cerclage removal
A transvaginal cervical cerclage is typically removed during week 37 of pregnancy — when a baby is considered full term — or earlier if you begin premature labor. A McDonald cerclage can usually be removed in a health care provider's office without anesthetic, while a Shirodkar cerclage might need to be removed in a hospital or surgery center. After having a transvaginal cervical cerclage removed at term, you'll typically be able to resume your usual activities as you wait for labor to begin naturally.
If you expect to have a C-section and plan to have children in the future, you might choose to leave a Shirodkar cervical cerclage in place throughout your pregnancy and after the baby is born. However, it's possible that the cerclage could affect your future fertility. Be sure to consult your health care provider about your options.
If you had a transabdominal cervical cerclage, you'll need to have another abdominal incision to remove the cerclage. As a result, a C-section is typically recommended during week 39 of pregnancy. Your baby will be delivered through an incision made above the cerclage. During the C-section, you can choose to have the cerclage removed or leave it in place for future pregnancies. Keep in mind that a cerclage could affect your future fertility.
The effectiveness of cervical cerclage is a topic of debate. Studies show that cerclage can help prolong pregnancy and prevent premature birth for women who have a history of miscarriages or premature births and a short cervix. However, it's not clear if the procedure will promote a baby's health. Keep in mind that the timing of cervical cerclage can also affect the outcome. The later cervical cerclage is done during pregnancy, the greater the risk that the procedure will stimulate preterm labor or rupture the membranes.
In most cases, a successful pregnancy after cerclage indicates the need for cerclage during future pregnancies. Consult your health care provider about your options.