What Is an Incompetent Cervix?

Medically Reviewed by Melinda Ratini, MS, DO on August 05, 2023
4 min read

An incompetent cervix is a condition where your cervix opens too early during pregnancy. It's also called cervical insufficiency. This can cause you to have a miscarriage or to give birth too early. If your doctor knows you have an incompetent cervix, it can be treated early in your pregnancy.

Your cervix is the bottom part of your uterus, which opens into your vagina. It's normally closed and firm. When you're pregnant and getting close to delivery, it softens, gets shorter, and opens so your baby can be born. When you have cervical insufficiency, your cervix may be high and soft before it's time for your baby to be born. If this happens, your baby may be born too soon.

An incompetent cervix is most often caused by some type of inflammation or infection. But there are several other conditions that can cause conditions that can result in cervical incompetence. Some are conditions you were born with, and some are conditions that happened later. These can include: 

  • Ehlers-Danlos syndrome is a disorder that affects your connective tissues such as your skin, joints, and blood vessels
  • Marfan syndrome, which is a condition that often affects the heart, eyes, blood vessels, and skeleton 
  • Injury to your cervix during a previous pregnancy
  • History of surgery on your cervix
  • Abnormally formed uterus or cervix
  • Short cervix, which is when your cervix is shorter than normal. 

You may not have any symptoms if you have cervical insufficiency. But warning signs may include: 

  • Mild discomfort or spotting when you are 14 to 20 weeks pregnant
  • Feeling pressure in your pelvis
  • Backache that you haven't had before
  • Abdominal cramps
  • Light bleeding
  • Change in your vaginal discharge

It can be difficult to diagnose an incompetent cervix. There are no tests that can diagnose it before pregnancy. Some tests, such as magnetic resonance imaging (MRI) or ultrasound, can be used to diagnose an abnormality that can cause an incompetent cervix before you get pregnant. 

After you become pregnant, your doctor will ask you about your medical history and symptoms. Your doctor may diagnose you with an incompetent cervix if you have a history of delivering during your second trimester, or if your cervix opens and thins before you're 24 weeks pregnant.  

Some tests your doctor may do to help diagnose an incompetent cervix include: 

Transvaginal ultrasound. Your health care provider may use this test to see if your membranes are protruding from your cervix. A thin wand is placed in your vagina. It sends out sound waves that are used to produce a picture.   

Lab tests. Your doctor may do an amniocentesis to see if you have an infection. In this test, your doctor checks a sample of your amniotic fluid to rule out an infection.   

Pelvic exam. Your health care provider may do a pelvic exam to see if your membranes are protruding from your cervix. If so, you may have an incompetent cervix.    

There are several treatment options your doctor might consider if you have an incompetent cervix. These may include: 

Cerclage. This is a stitch in your cervix to help hold it closed. It's usually done between 12 and 14 weeks of pregnancy. The stitch will be removed around 27 weeks of pregnancy. If you're pregnant with twins or multiples your doctor won't do a cerclage because it hasn't been shown to help in those cases. 

Progesterone treatment. Progesterone is a hormone. If you have a history of giving birth too early, your doctor may give you shots of progesterone every week during your second and third trimester.     

Bed rest. If your doctor discovers you have an incompetent cervix later in your pregnancy, they may put you on bed rest for the rest of your pregnancy. This means you need to stay in bed and not do your normal activities.

Some risks associated with an incompetent cervix can include:

There's no way to prevent an incompetent cervix. There are many things you can do to make your pregnancy as healthy as possible, including: 

Eat a healthy diet. When you're pregnant you need more folic acid, calcium, iron, and other nutrients. Taking a prenatal vitamin will help you get the nutrients you need.  

Gain the right amount of weight. If you were at a healthy weight before you got pregnant, you should probably gain between 25 and 35 pounds. Gaining enough weight, but not too much, will help your baby develop and grow.   

Get regular prenatal care.  Seeing your doctor regularly during your pregnancy is important to monitor your and your baby's health. Make sure you tell your doctor about your medical history, including any problems you've had in previous pregnancies.   

Abstain from harmful substances. Check with your doctor before you take any medicines, including over-the-counter and herbal medicines. Quit smoking if you smoke. Avoid alcohol and illegal drugs.