I have an incompetent cervix. How can I keep my baby?

Author: Zou Liying, Chief Physician, Beijing Obstetrics and Gynecology Hospital, Capital Medical University

Reviewer: Teng Xiuxiang, Chief Physician, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University

We often compare the uterus to a warm little house where the baby lives for 10 months before birth. The uterus is divided into the uterine cavity and the cervix. The cervix is ​​equivalent to the door of the house. When the fruit is ripe, this "door" will open and the baby will come out of this door.

Before the baby matures, this "door" is closed. As the baby grows older, the pressure on this "door" gradually increases. If this "door" suddenly opens before the baby matures, the baby will not be able to stay in the uterine cavity, and premature birth or late miscarriage will occur. This condition is called cervical insufficiency.

Figure 1 Original copyright image, no permission to reprint

1. What causes cervical insufficiency?

There are innate reasons and acquired reasons.

Congenital causes are relatively rare, and the main cause is problems with cervical development, which manifests as: no history of miscarriage, premature birth, or cervical injury. Cervical insufficiency occurs directly in the first pregnancy, leading to late miscarriage or premature birth.

Acquired causes are more common, such as a history of pregnancy and childbirth, which may cause damage to the cervix during vaginal delivery, or damage to the cervix during induced labor. For example, repeated artificial abortions may cause damage to the cervix. Cervical diseases, such as cervical carcinoma in situ, require surgery, which may also cause damage to the cervix. From this point of view, any damage to the cervix may cause cervical insufficiency.

2. How is cervical insufficiency detected and diagnosed?

We hope to detect cervical incompetence early, but in fact, there are still many limitations in its understanding and diagnosis. Clinical diagnosis of cervical incompetence is mainly based on the following three aspects:

First, based on medical history. If there is a history of late miscarriage or premature birth caused by typical cervical insufficiency, it can be inferred from the medical history whether it is a cervical problem. About 1/5-1/4 is caused by cervical insufficiency.

Second, ultrasound examinations during pregnancy are used to diagnose the baby. Ultrasound diagnosis is usually combined with medical history. For women with a history of late spontaneous abortion (late spontaneous abortion refers to spontaneous abortion that occurs between 12 and 28 weeks of pregnancy), ultrasound screening of cervical length should be performed starting from 14 weeks of pregnancy. For women with premature births after 28 weeks of pregnancy, ultrasound screening of cervical length should be performed starting from 16 weeks of pregnancy.

In addition to looking at the length of the cervix, cervical ultrasound screening also looks at the shape of the cervix. Under normal circumstances, the cervix is ​​in a "T" shape, with the internal opening closed. If the internal opening is open and then expands to the external opening, it will be in a "V" shape. If the external opening is also open, it will be in a "U" shape.

Whether looking at the length or shape of the cervix, it must be combined with medical history. A short cervix combined with a history of late spontaneous abortion or premature birth can be diagnosed as cervical insufficiency. For pregnant women without any history of abortion or premature birth, even if the cervix is ​​short, it is not necessarily cervical insufficiency. In this case, the length of the cervix can be dynamically monitored.

The third is non-pregnancy examination. If you have a history of late spontaneous abortion or premature birth, and suspect that it is caused by cervical abnormalities, you can test the function of the cervix during the non-pregnancy period. If the No. 8 dilator can pass freely, it means that the cervix is ​​incompetent, because it cannot pass under normal circumstances. However, it is currently believed that the accuracy of the non-pregnancy examination is not high. If it cannot pass, it cannot completely deny the incompetence of the cervix, so it is still important to dynamically monitor and evaluate the length of the cervix during pregnancy.

3. How to treat cervical insufficiency?

The most effective treatment for cervical insufficiency is cervical cerclage, which involves tying the cervix with thread.

Figure 2 Original copyright image, no permission to reprint

Generally speaking, cervical incompetence is treated after pregnancy. It is usually recommended to perform cervical cerclage vaginally at 12-14 weeks of pregnancy. It should also be combined with the gestational age of the last miscarriage. For example, if the last miscarriage occurred at 14 weeks of pregnancy, cervical cerclage cannot wait until 14 weeks of pregnancy, but should be performed at 12-13 weeks of pregnancy.

There is another situation where you don't know you have cervical incompetence, you don't have abdominal pain, your cervix is ​​dilated, and the fetal sac is protruding. It is clear that it is caused by cervical incompetence. In the absence of uterine contractions, the fetus is still alive, and the fetal membranes are intact, you can do an emergency cervical cerclage. If you have uterine contractions, the contractions can't press down, and the contractions push the fetus out little by little, doing a cervical cerclage in the presence of resistance may cause cervical laceration, so this cerclage cannot be done.

The cervical cerclage should be done with non-absorbable thread. If absorbable thread is used, it will be ineffective after being absorbed. It is best to tie the cervix at the level of the internal os of the cervix. After the cervix is ​​tied at the level of the internal os, there is still the cervical canal below. Under normal circumstances, there will be a mucus plug in the cervical canal. The mucus plug is a good protective barrier that can prevent bacteria in the vagina from entering the uterine cavity.

Vaginal cervical cerclage is relatively insignificant and is suitable for most patients with cervical insufficiency. At 37 weeks of pregnancy, the sutures can be removed vaginally and then wait for natural delivery. If you want to get pregnant again in the future, you need to do cervical cerclage again, because the cervical function is not good, and cervical cerclage should be done every time you get pregnant to help strengthen the cervical function. If premature birth occurs due to other reasons, regular uterine contractions occur, and delivery is imminent, the sutures must be removed urgently at this time, because the cerclage is still there when the contractions are very strong, which can easily cause cervical lacerations.

If the cervix has been operated on before and is very short, cervical cerclage cannot be performed vaginally. Then it must be performed transabdominally, entering the abdominal cavity and performing cerclage at a higher position on the cervix. Transabdominal cervical cerclage can be performed laparoscopically or laparotomy. The surgical injury is relatively large, and the sutures must be removed through the abdomen. Therefore, transabdominal cervical cerclage is mostly performed during the non-pregnancy period.

If you plan to get pregnant and have cervical incompetence, you should tie the cervix through the abdomen before getting pregnant. Because the cerclage is located high and cannot be removed through the vagina, you will have to terminate the pregnancy by cesarean section. If you want to get pregnant again in the future, you don't have to remove the cerclage first. If you don't plan to get pregnant again in the future, you can remove the cerclage at the same time as the cesarean section.

The damage caused by transabdominal cervical cerclage is relatively large. We will only consider transabdominal cerclage when transvaginal cervical cerclage fails or is not possible.

4. What issues should be paid attention to after cervical cerclage surgery?

If you experience abdominal pain, bleeding, or vaginal discharge after cervical cerclage, go to the hospital immediately.

After the cervical cerclage, the patient is relatively stable and has no other abnormalities. She can live and have prenatal checkups like a normal pregnant woman. It is not recommended to stay in bed for a long time, as it will cause other problems, such as blood clots and limb atrophy. There is no problem living a normal life after the cervical cerclage, but it is not recommended to do some strenuous activities.

Eat a balanced diet, eat some crude fiber foods, eat less spicy and irritating foods, and prevent constipation. Pay attention to clean diet, unhygienic diet is easy to cause diarrhea. After cervical cerclage, it was originally good, but diarrhea and constipation caused uterine contractions, cervical lacerations, premature rupture of membranes, etc., and finally the baby could not be saved, which was not worth the loss.

Cervical cerclage is the most effective method for treating cervical insufficiency, which can prevent late spontaneous abortion and premature birth, but it cannot be guaranteed to be 100% effective. Generally speaking, if cervical cerclage is done in a planned way, the effect is relatively good, and the effective rate can reach more than 90%. The key to success lies in early detection, early diagnosis, and early intervention.