Cervical Length During Pregnancy

Woman holding pregnant belly

Every pregnant woman wants a healthy baby. While there are several factors that influence pregnancy, some of them can cause serious complications, one of them being the cervical length. This article will help you understand everything you need to know about the cervical length and how it can affect your pregnancy.

What is Cervical Length?

The cervix is a canal around two to three centimetres in the lower section of the uterus. It connects the uterus to the vagina. Cervical length is simply the length of the canal inclusive of the cervical opening. Cervical length changes over time, with menopausal women sporting a cervix less than a centimetre in length. However, in pregnant women, the cervical length needs to be within a particular range for a successful pregnancy.

Importance of Cervical Length

The cervix is inflexible until you get pregnant. Then it slowly becomes softer, shorter, loses muscle tone, and dilates. This is known as cervical effacement, which allows the foetus to fit inside the cervical canal while being born. However, if your cervical length is too short, there is a high chance you might spontaneously undergo preterm uterine contractions. This could lead to preterm labour, and all the complications involved with premature birth.

Does Short Cervix Mean the Same as Cervical Insufficiency?

No, short cervix and cervical insufficiency are completely different things. A short cervix merely refers to the length of the cervical canal. Cervical insufficiency, on the other hand, refers to premature cervical effacement and dilation that happen with the muscles of the uterus and cervix are unable to remain firm and strong. However, cervical insufficiency can lead to a short cervix.

Factors That Influence the Cervical Length

There are several factors that could impact the required cervical length for normal delivery. Some of them are:

  • Anatomy: Not all women are built the same. Just as there are differences in height, weight and breast size, some women just have naturally short cervixes.
  • Uterine Inflammation: An inflamed uterine lining is known to cause a reduction in cervical length.
  • Distended Uterus: If you have are carrying two or more babies, there is a chance your uterus will stretch far beyond its capacity. This could lead to the uterus pushing downwards on the cervix, reducing its length.
  • Pregnancy Complications: Infections and bleeding during your pregnancy have a tendency to cause cervical irritation, thereby affecting its length.
  • Cervical Insufficiency: Cervical insufficiency or an incompetent cervix is a condition caused due to lack of cervical muscle strength, which can influence cervical length.

How is Cervical Length During Pregnancy Determined?

An ultrasound transvaginal scan is your best option to keep a tab on cervical length. When your doctor performs this scan, you will be able to clearly observe the cervix as a single tube leading to the uterus from one end and the vagina from the other. The cervical length is then measured from the images obtained. Normal cervical length during pregnancy in the 24th week is about 3.5-5 cm, whereas the cervical length at 28 weeks is approximately 3.5 to 4 cm, and the cervical length at 32 weeks is between 3-3.5 cm. Cervical length lower than 2.5 cm is considered short, while cervical length below 2 cm increases the likelihood of preterm birth.

Is There a Need for Measuring Cervical Length During All Pregnancies?

The cervical length scan is not required for normal pregnancies. It is usually recommended for women who are carrying multiple foetuses and have a history of premature birth and miscarriages. The scan can also be performed if you have a genetic predisposition towards preterm labour, miscarriages and multiple pregnancies.

What Does the Doctor Do If Cervix Length is Small?

Here are a few recommendations your doctor might make if your cervix is too short.

Bed Rest: Bed rest is one of the chief preventative measures for women at risk of giving birth prematurely. Lying down helps take the pressure of the uterus and your growing baby off the cervix, preventing it from effacing early.

Pregnant woman on bedrest

Cerclage: This is a minor surgery in which your doctor will stitch your cervix shut with a couple of sutures. The procedure is quick and performed under anaesthesia. It is done for women who have had prior preterm deliveries. Some doctors believe that cerclages can lead to infection and inflammation, but these can be controlled with the right medications.

Hormonal Treatment: In this treatment, your doctor will place the pregnancy hormone, progesterone, in the cervical area. Progesterone can prevent the initiation of labour.

Pessary: A silicone device known as a pessary can be used to support the cervix, keeping it closed shut.

Technical terms like cervical length sound scary and complex. However, it is important for you to know the changes your body is going through. If you have any concerns about cervical length during your pregnancy, make sure to consult your doctor.

Also ReadA Guide To Cervix Dilation During Labour and Birth