What is incompetent cervix?

In the female reproductive system, the cervix is the lower end of the uterus. The cervix is the part of the uterus which opens into the vagina.

Before pregnancy, the cervix is normally firm and closed. During pregnancy, the cervix softens, shortens and dilates (opens) so you can give birth. Incompetent cervix occurs when the cervix opens too early and silently during the pregnancy.

Incompetent cervix is also known as cervical insufficiency. It can cause problems including miscarriage (a fetus that dies before birth) and premature birth (a baby born before organs are fully developed).

How common is incompetent cervix?

Incompetent cervix occurs in about 1 in 100 pregnancies.

What causes incompetent cervix?

Several conditions can cause incompetent cervix. They include:

  • Abnormally formed uterus or cervix.
  • Previous cervix surgery.
  • Short cervix.
  • Damaged uterus from previous miscarriage or childbirth.
  • Exposure to diethylstilbestrol (DES), a synthetic (human-made) hormone given to some women in the past to help them have successful pregnancies.

What are the symptoms of incompetent cervix?

Incompetent cervix does not have signs or symptoms. Doctors diagnose most cases after a miscarriage in the second trimester of pregnancy.

Your doctor will monitor your cervix closely throughout your pregnancy if you have had previous miscarriages or risk factors for the condition. This monitoring includes a test called a transvaginal ultrasound (ultrasound using a wand inserted in the vagina), which allows the doctor to see the cervix.

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