Short cervix during pregnancy is a pathological condition in which the length of the organ is less than the minimum values for a certain gestational period. In most cases, it is asymptomatic, detected by ultrasound screening. The appearance of clinical symptoms in the form of vaginal discharge and abdominal pain indicates a high risk of termination of pregnancy. To make a diagnosis, the examination data on the chair is supplemented with the results of cervicometry and, if necessary, the determination of the hormonal background. Treatment is combined with the use of tocolytics, hormone therapy, the installation of an obstetric pessary or suturing of the cervical canal.
Shortened cervix is one of the most common causes of miscarriage. According to specialists in the field of obstetrics and gynecology, from 15 to 42% of late spontaneous abortions and premature births are provoked by this pathology. Signs of a short neck are detected in almost every 10th pregnant woman. The diagnosis is usually made at 15-20 weeks of gestation. The length of the organ less than 3 cm at the 20th week of gestation is considered critical for the continuation of pregnancy. A direct indication for surgical correction of the disorder is shortening of the neck to 2.0 cm or less by the end of the second trimester. Pathology is more often determined in repeat-giving women, which is associated with possible traumatism in past childbirth.
Clinically significant shortening of the isthmic-cervical zone occurs in the presence of pathological changes in the tissues of the cervix, its hypersensitivity to the action of regulatory hormones or an increase in their concentration, pressure of the growing fetus and its membranes on the lower uterine segment. The immediate causes of the formation of a shortened neck are:
- Anatomical defects and mechanical damage. Initially, a short neck occurs with genital infantilism, congenital abnormalities uterus or cervical canal. Deformity with a decrease in the length of the organ is possible due to trauma received in previous childbirth or during invasive manipulations (diagnostic curettage, abortion).
- Hormonal disorders. The state of the cervix is affected by hormones produced by the ovaries and placenta during pregnancy. Most often, its shortening is observed with increased secretion of androgens. The occurrence of pathology is also facilitated by connective tissue dysplasia caused by an increase in the level of relaxin as labor approaches.
- Pressure on the isthmic-cervical region. The probability of stretching of the lower uterine segment and the internal throat of the cervix with its decrease increases from the 2nd trimester of pregnancy, when faster fetal growth begins. Risk factors are multiple pregnancies and polyhydramnios, in which the pressure on the cervix from inside the uterus is higher.
The mechanism of pathological disorders in the shortening of the cervix is associated with changes occurring in its tissues during pregnancy and increased pressure in the uterine cavity. Normally, after conception, the cervical canal closes, its mucosa becomes edematous and cyanotic due to accelerated blood supply, and the size of the cervix gradually increases, reaching a maximum value of 3.5-4.5 cm at 28 weeks. By the end of pregnancy, the neck gradually shortens, opens and smoothes. In the presence of congenital or acquired anatomical defects, dishormonal influences, the closing function of the cervical canal is disrupted. As a result, under the pressure of the fetus, the internal and then the external uterine pharynx stretch, the neck becomes shorter. However, at the same time, it usually does not soften and does not reach the necessary degree of maturity for childbirth.
Pathology in more than 80% of cases proceeds covertly, is diagnosed with routine ultrasound screening in the second trimester of pregnancy. The presence of a short neck may be indicated by the appearance of watery or bloody vaginal discharge, minor pulling pains in the lower abdomen, which become cramping as the disorder progresses. However, such disorders are characteristic of pronounced violations of the closure function of the cervix, occur with a high threat of premature termination of pregnancy, which increases the importance of routine examinations.
The most serious consequence of a short and deformed cervix is an increasing cervical insufficiency. In the presence of such pathology, the risk of spontaneous miscarriage and premature birth increases. The failure of the cervical canal contributes to the upward spread of genital infections with the development of endometritis, chorioamnionitis, and other inflammatory processes. If a woman with a short neck is pregnant, she may experience rapid childbirth with ruptures of the vagina and perineum, intranatal injuries of the child.
Due to the almost asymptomatic course of the disorder and the absence of its visible external signs, instrumental methods play a leading role in making a correct diagnosis, allowing you to accurately determine the size, condition and shape of the cervix. The most informative in diagnostic terms are such studies of a pregnant woman as:
- Gynecological examination. The method is more indicative in repeat-giving patients with the expansion of the cervical canal along the entire length. The increase in the diameter of the external pharynx is clearly noticeable during the examination of the neck in mirrors. With a significant shortening, it passes the finger of the obstetrician-gynecologist, fetal membranes can protrude through it. Palpation provides only approximate data on the possible size of the organ.
- Cervicometry. Transvaginal ultrasound determination of the length of the cervix, the diameter of its internal and external pharynx, the condition of the cervical canal is the gold standard for the diagnosis of the disorder. As a screening, the method is shown to all pregnant women with a period of 18-22 weeks. With a burdened obstetric history, cervical ultrasound is performed in the 1st trimester. Unscheduled sonography is performed if a shortening of the organ is suspected.
- Determination of hormone levels. If anatomical prerequisites for the development of pathology are not identified, laboratory tests are shown to assess the concentration of hormones. With functional shortening of the neck, there may be an increase in the concentration of androgens, a decrease in the content of progesterone. In a small number of pregnant women with a shortened neck, the level of relaxin is increased, but the data of this analysis are rarely used.
A short neck is differentiated from other pathological conditions that have characteristic signs of early termination of pregnancy, such as detachment of a normally located placenta, its presentation or infarction, leakage of amniotic fluid, etc. In doubtful cases, consultations of related specialists are prescribed — an endocrinologist, an infectious disease specialist, an immunologist.
Medical tactics after the pathology is detected depends on the gestational age, the degree of shortening of the organ, the presence or absence of a threat of termination of pregnancy, the burden of obstetric history with habitual miscarriages or premature birth. All patients are recommended to limit physical and emotional stress, sufficient rest and a night’s sleep. To achieve the best results, pharmaceuticals are usually combined with small invasive techniques. Pregnant women with this disorder are shown:
- Drug therapy. To reduce pressure on the lower segment of the uterus, in addition to wearing a bandage, patients are prescribed antispasmodics and tocolytics that reduce the tone of the uterine muscles. In the presence of hormonal disorders, it is possible to use drugs that regulate the secretion of hormones. Herbal remedies with sedative effect are used to correct emotional disorders.
- Installation of an obstetric ring (pessary). During the manipulation, a special device is put on the cervix, which keeps it closed. The method of non-surgical prevention is effective with a slight shortening of the organ in 2-3 trimesters. The pessary allows you to compensate for the fetal pressure on the cervical region and prolong pregnancy. The device is selected individually, taking into account the size of the organ.
- Cervical cerclage. Surgical intervention for suturing the uterine neck is performed at 14-25 weeks of pregnancy. During the operation, circular pouch or U-shaped sutures are applied around the cervical canal to prevent its expansion. Stitches are removed after the discharge of amniotic fluid, the onset of labor, the occurrence of bleeding or upon reaching the 38-week gestation period.
Prognosis and prevention
The prognosis of pregnancy with a shortened cervix depends on the time of pathology detection and an adequate choice of pregnancy management tactics. With careful implementation of medical recommendations, correction of the motor regime and reduction of loads, the probability of carrying a child up to 38-40 weeks increases. For preventive purposes, it is recommended to plan pregnancy, refuse abortions and unjustified invasive interventions on the uterus, early registration in a women’s clinic and timely passage of ultrasound screenings, especially with traumatic childbirth and a history of uterine pathology.