Cervical Incompetence and Cervical Cerclage

Cervical Incompetence and Cervical Cerclage

  Autor NN Team Data: 19.11.2007

Cervical Incompetence and Cervical Cerclage
In case of a normal pregnancy, the cervix remains closed until the moment of birth when it starts to dilate and to thin in order to allow the fetus to pass. 

But sometimes, the thinning and the dilation of the cervix starts prematurely, not being caused by the birth but by the cervix weakness. This condition is called cervical incompetence and may have different causes, the most important of them being the cervix trauma. 

An incompetent cervix cannot sustain the fetus weight and dilates without contractions or pain, sometimes being open completely. Because of the dilation, the amniotic membranes "fall" through the opening and get torn, thing which irritates the uterus and lead to the labor start, this happens many times before the fetus is able to survive outside the uterus. In many cases, the labor is too advanced to be stopped. 

The factors that lead to cervical incompetence are: cervical incompetence in a previous pregnancy, history of medical surgeries before the pregnancy, cervical injuries or anatomical defects of the cervix. The studies have indicated that the risk for cervical incompetence depends on the number and severity of dilations if the woman suffered surgical dilation of the cervix.  

If the surgical dilation of the cervix took place after a miscarriage, there are small chances to develop a cervical incompetence. Regarding the induced abortions, it has been noticed that only after three such surgeries, the risk of cervical incompetence increases with 12%. 

Women with cervical incompetence suffer from what is called "silent" dilation, meaning dilation of the cervix with minimum contractions and without pains between the 16 and 28 weeks of pregnancy. The cervix dilation is quite large (2 cm or even more) and the symptoms are minimum. When the dilation reaches 4 cm, there might start active, painful contraction and the membranes might tear. 

The diagnosis of cervical incompetence is establishes through a physical examination and a hysterosalpingography, but also through anamnesis. If the mother had miscarriages in the second or third trimester in the past, she might be suspect of cervical incompetence. 

Once the diagnosis is established, the condition might be treated with a surgery called cerclage. The cerclage consists in placing strong sutures above the opening of the cervix in order to stay close and it is done either through the vagina or through an abdominal incision. 

This surgery is usually done after 12 weeks of gestational age, when the risks of a miscarriage from other reasons than cervical incompetence are very small, but before 28 weeks of pregnancy. The cerclage is not done if the membranes are already torn, the labor has started, there is an infection, the fetus has abnormalities or if there are vaginal bleedings without a known cause. 

After the surgery, the mother is closely monitored because sometimes the cerclage might cause contractions or infections. Also, the doctors recommend rest in bed in order not to put too much pressure on the cervix, thus extending the pregnancy period until the baby can survive by himself. 

The cerclage is usually removed in the 37 week of pregnancy, and the labor starts quite shortly if the diagnosis of cervical incompetence was correct. If the cerclage was done through abdominal incision, the doctor will perform caesarian section and it is possible for the sutures to be maintained for the following pregnancies. 

Read the English version of this article: Cervical Incompetence and Cervical Cerclage