The cervix during pregnancy
In order to ensure that the pregnancy runs as smoothly as possible, preventive medical checkups are carried out approximately every four weeks. Among other things, the weight and blood pressure of the expectant mother are checked and documented, and urine tests are performed. Of particular importance during these check-ups is also the examination of the uterus.
The cervix (cervix uteri) with its opening, the cervix, is of particular interest. During pregnancy, this is usually tightly closed by a plug of mucus to prevent pathogens from entering the uterus. In order to provide a strong base for the uterus with the child growing inside, the muscle tissue of the cervix is also hardened.From about the 36th week of pregnancy, however, it begins to become more pliable and softer under the influence of the hormone prostaglandin F2a.
At the same time, the cervix uteri shortens and finally the uterus straightens up due to the so-called maturing contractions. All these are signs that the uterus is preparing for the approaching birth. For this reason, special attention is paid to the length of the cervix during prenatal care.
It should not be less than 25 mm until shortly before the birth. Excessive shortening of the cervix before birth carries the risk of cervical weakness (“cervical insufficiency”), i.e. premature opening of the cervix. The softening of the uterine tissue that occurs in this process can be felt by the doctor.
If a cervical insufficiency is actually detected, it can then be treated to a certain extent depending on the cause. The condition of the cervix (“cervix uteri”), as well as its length and external appearance, provide the respective examiner with valuable information on the progress and course of a pregnancy. The cervix should maintain a relatively constant length and compression strength until shortly before birth.
A length of 25 mm or longer is considered harmless. Either by palpation or by means of vaginal ultrasound, this length can be recorded with millimeter precision at every preventive examination and then documented in the maternity record. Measuring the length of the cervix is essential, especially since a shortened cervix can develop into a cervical weakness (“cervical insufficiency”).
The final consequence is that the base of the uterus can no longer support the weight of the child, so that the cervix may open prematurely. Any untreated cervical insufficiency therefore carries the risk of premature birth. A shortened cervix can have many causes.
Mental stress can play a role, as can physical overexertion or increased production of amniotic fluid (which in turn can be due to a number of possible causes). However, the most common reason for cervical shortening is ultimately an ascending undetected infection and the resulting premature labor. Mothers of multiple pregnancies are particularly affected by premature shortening of the cervix.
First-time mothers, however, are rarely affected by cervical insufficiency. Despite the potentially serious consequences for the pregnancy, cervical shortening occurs without major discomfort or other symptoms. For this reason, it is essential that the pregnant woman is aware of the preventive examinations.
If a cervical shortening has been detected early, there are various treatment options with usually good treatment prospects, so that the birth can be delayed until shortly before the originally planned date if these measures are consistently followed. The most important measure is always physical protection and the best possible avoidance of stress. Depending on the extent of cervical shortening, the degree of protection required can range up to strict bed rest.
In any case, the pregnant woman concerned should make sure that she takes many breaks and consciously allows herself plenty of time in her daily activities. Some therapists also prescribe magnesium therapy as a support, which is intended to relax the muscle tissue of the uterus. If an infection is proven to be the cause of a shortened cervix, antibiotics are the therapy of choice.
Tears in the tissue of the cervix, vagina or perineum can also be treated surgically. Another treatment option is the placement of a so-called cerclage. In medicine, this is generally understood to mean wrapping a band around an organ or structure.
In the case of a cerclage, a band is wrapped around the cervix to give it more support and resistance to the child’s weight. However, for some years now this method has been considered critical, as it seems to be an effective therapy to prevent premature birth only in exceptional cases and at the same time carries the risk of stimulating additional uterine contractions. In case of severe cervical insufficiency, hospitalization is strongly recommended.Premature contractions can be inhibited here with tocolytics, which can gain valuable days to prepare mother and child for birth.
