Do You Know Your Cervical Length? If You’re Pregnant, You Should

A baby is born preterm roughly every minute in the United States. I’ve seen the data many times and know women who have gone into labor before 37 weeks of pregnancy, and still this statistic seems staggering to me. If science has found a way to induce labor, surely doctors must be able to do the opposite. New research suggests that there’s hope—and it starts with a ruler. Okay, so not your standard elementary-school staple, but a tool that measures the length of your cervix, called the CerviLenz, which is inserted into the vagina and measures the length of the outer wall of the cervix. During pregnancy, the cervix shortens as your due date approaches to allow the baby to enter the birth canal. But in some women, it shortens too soon, making them six times more likely to go into labor early.

Who needs to have their cervical length measured and when? We know that there are certain risk factors for preterm birth, such as a previous history, high stress levels, being pregnant with twins or more, and smoking, but the fact is that it can happen to any woman, so every woman should get measured around 20 weeks and again around 24 weeks of gestation. For those women who are diagnosed with a short cervix (less than 20 millimeters), research has shown that treatment with progesterone, a naturally occurring hormone during pregnancy, can reduce the likelihood of preterm labor by 45 percent.

Until this precaution becomes mainstream, the best thing you can do is to be your own advocate. Ask your doctor about getting your cervix measured. For more information, visit

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  1. by Angela Davids

    On November 30, 2011 at 10:15 am

    A big thanks to for sharing this information! Studies have proven that cervix length is an excellent predictor of a woman’s risk of preterm birth. There’s more on that research here:

  2. by Faye

    On December 16, 2011 at 2:58 pm

    i am in hospital now, admitted to stop contractions and a cervix that was ‘funneling’ and a length of 1.8 – which is why they sent me to hospital. its very important to know the length. i am having twin boys, but it can happen to anyone. i have been sent to hospital twice because of this. thanks for bringing something up that most people dont consider till its too late!