Uterine hypertension in pregnancy is a pathological condition in which the tonic tension of the myometrium increases before the expected date of delivery. It is manifested by discomfort, pain, tension in the pelvis, abdomen, lower back, sacrum, perineum, increased density of the uterine wall, with a more severe course — increased urination, urge to defecate, changes in fetal activity. It is diagnosed by palpation, ultrasound of the uterus, tonusometry, assessment of hormone levels. Antispasmodics, tocolytics, sedatives, progestogenic drugs are used for treatment.
ICD 10
P03.6 Fetal and newborn lesions caused by uterine contractile disorders
General information
Normally, the smooth muscle fibers of the myometrium are always in a tonally reduced state, creating a pressure in the uterine cavity from 8 to 12 mm Hg. With an increase in intrauterine pressure above these indicators, they indicate a physiological or pathological increased tone. The prevalence of the disorder during pregnancy reaches 60-65%. The probability of its development after 35 years increases by 3 times, which is associated with an increase in the number of gynecological diseases, abortions, diagnostic and therapeutic invasive interventions. The risk group consists of pregnant women who work in hazardous industries or on a daily basis, do not sleep enough, smoke, drink alcohol, are divorced or have a conflict relationship with a partner.
Causes of uterine hypertension in pregnancy
The contractile activity of the myometrium increases as a result of neurohumoral influences and pathomorphological changes in the muscular layer of the uterus. Sometimes the increase in tone has a physiological character (contractions of the uterine muscles during sexual intercourse, training contractions in the second half of the gestational period). However, in most cases, increased tonic activity indicates the development of pathological processes that pose a threat to the normal course of gestation. The tone of the uterus increases under the influence of such reasons as:
- Hormonal imbalance. Tonic contractions of smooth muscle cells of the myometrium are intensified in conditions of progesterone deficiency. Hypoprogesteronemia occurs with an increased content of androgens in pregnant women with ovarian or adrenal steroidogenesis disorders, an increase in prolactin levels in hypothyroidism, polycystic ovary syndrome, liver cirrhosis, pituitary tumors, taking antiemetics and antihistamines.
- Overgrowth of the uterine wall. Muscle fibers reflexively contract with significant stretching of the walls by the growing child and his shells. An increase in uterine tone is more often observed in patients suffering from polyhydramnios, carrying a multiple pregnancy, a large fetus. At normal sizes of a single fetus, the myometrium overgrows in women with genital infantilism, developmental abnormalities (saddle uterus, etc.).
- Pathological changes in the uterine wall. Inflammatory and neoplastic processes in the mucous, muscular, and serous membranes of the uterus reduce its ability to stretch and create foci of pathological impulses that cause local or generalized muscle contractions. The causes of increased tone can be interstitial and submucosal fibroids, endometriosis, cervicitis, endometritis, adhesions in the pelvis.
- Disorders of nervous regulation. Normally, before the 38-39 th week of pregnancy, the excitability of intrauterine receptors, spinal cord and areas of the cerebral cortex responsible for uterine contractions is minimal. With emotional stress, significant physical exertion, acute infections with hyperthermia (influenza, ARVI, angina), a site of excitation may form in the central nervous system, the activity of which negatively affects the tone of the uterus.
An increase and increase in contractions of the myometrium, which can provoke termination of pregnancy, is also observed in immune disorders (Rh conflict, isoimmune incompatibility), when the uterus tries to get rid of the child, perceived as a foreign organism. A similar situation occurs when there are anomalies of fetal development incompatible with life or its antenatal death.
Pathogenesis
The key link that leads to the appearance of increased uterine tone during pregnancy is the increased contractility of muscle fibers under the influence of external or internal stimuli. The physiological tone of the myometrium is provided by the autonomous nervous system. The increase in contractility is hindered by progesterone, which relaxes smooth muscle fibers, and the gestational dominant — a focus of arousal that is formed in the cerebral cortex under the influence of afferent impulses from the introreceptors of the uterus and inhibits nervous processes that can disrupt gestation. With this in mind, specialists in the field of obstetrics distinguish two mechanisms for enhancing uterine tone — humoral and neurogenic.
In the first case, an increased tonic contraction develops in response to a decrease in progesterone levels, in the second — due to the occurrence of a pathological focus of excitation in the central nervous system or a weakening of the gestational dominant due to changes in the flow of nerve impulses from the pregnant uterus in case of its overstretching, the presence of inflammatory processes, neoplasia. Sometimes humoral and neurogenic links of pathogenesis are combined. Increased physiological contraction of the myometrium is accompanied by an increased release of catecholamines and other bioactive compounds into the blood during physical exertion, emotional experiences, intimacy, vaginal examination, fetal movements.
Classification
The main criteria for systematizing the increase in uterine tone during pregnancy are the nature, intensity and duration of pathological sensations, and the frequency of their occurrence. This approach makes it possible to develop optimal tactics for accompanying a pregnant woman and to prevent the termination of gestation in time. There are 3 degrees of severity of high myometrial tone:
- I degree. A pregnant woman is concerned about minor or moderate short-term pain in the lower abdomen. Uncomfortable sensations and uterine compaction disappear at rest without prescribing medication.
- II degree. More pronounced soreness is noted not only in the lower abdomen, but also in the lumbosacral spine. The uterus is significantly compacted. To eliminate pathological symptoms, antispasmodics are required.
- III degree. Intense painful sensations in the abdomen, sacrum and lower back are noted even with small physical exertion and emotional experiences. Palpationally, the uterus is very hard. The pregnant woman must be hospitalized.
Symptoms of uterine hypertension in pregnancy
A sign of increased contraction of the myometrium is the appearance of discomfort in the pelvic region. A woman complains of pulling or bursting pain of varying intensity — from mild to severe, localized above the pubis, in the lower abdomen, in the sacrum, lower back, sometimes in the perineum. At the same time, there is a feeling of tension and “hardening” of the abdomen, in which a compacted uterus is palpated through the abdominal wall in the 2-3 trimesters of pregnancy. In some patients, urination becomes more frequent, there are urges to defecate, fetal movements become more intense. In mild cases, signs of increased tone pass with deep, calm breathing in the supine position. With the progression of the condition, the tonic contraction of the uterine muscles can turn into contractions.
Complications
An increasing increase in the tone of the smooth muscle fibers of the uterus can provoke an early or late miscarriage in the first half of pregnancy and premature birth in the second. Reduction of the uterine wall is often accompanied by a violation of blood flow in the vessels of the uterus and placenta, deterioration of the blood supply of the child. With a frequent increase in the tone of the II-III degree, fetoplacental insufficiency, intrauterine fetal hypoxia, and a delay in its development may occur. The disorder increases the risk of premature discharge of amniotic fluid, cervical insufficiency, detachment of the normally located placenta. In childbirth, patients who noted an increase in uterine tone are more likely to experience violent labor activity, discoordinated contractions of the myometrium.
Diagnostics
The main task of the diagnostic search for uterine hypertension in pregnancy is to establish the causes of the disorder, to assess its effect on the course of gestation. In some cases, the condition does not manifest clinically and becomes an accidental finding during ultrasound screening of pregnancy. Recommended methods of examination in case of suspected increase in uterine muscle tone are:
- Palpation of the abdomen. With normal tone during 2-3 trimesters of pregnancy, the abdomen is soft, at long gestation periods, the position and presentation of the child is easily determined through the uterine wall. The increased tone is indicated by the compaction and tension of the uterine wall, sometimes reaching a degree of rocky hardness. The fetus cannot be palpated.
- Ultrasound of the uterus. The uterine wall is locally or totally thickened due to the contraction of muscle fibers. With a small area of compaction, clinical symptoms may be absent. The method allows you to detect signs of placental abruption in time. In case of possible fetoplacental insufficiency, ultrasound is supplemented with dopplerography of uteroplacental blood flow.
- Tonusometry. The degree of contraction of the myometrium is estimated in conventional units measured by special tonusometers. The sensor of the device is installed above the projection of the uterus, after which the depth of immersion of its pin into the uterine wall is recorded on the scale of the device. Spring and electric tonusometers are used for the study.
- Analysis of the level of sex hormones. Since increased uterine contractility is often associated with dishormonal conditions, the causes of pathology can be identified using laboratory diagnostic methods. In pregnant women with high uterine tone, a reduced progesterone content, an increased concentration of testosterone, prolactin can be determined.
As additional methods of examination, cervicometry is recommended, which allows detecting shortening of the cervix, CTG, fetometry and phonocardiography of the fetus, aimed at timely detection of a threat to the child. Differential diagnosis is carried out between various diseases accompanied by increased myometrial tone, as well as natural local thickening of the uterine wall at the site of fetal implantation. According to the indications, the pregnant woman is consulted by an endocrinologist, an infectious disease specialist, a neurologist, a psychotherapist.
Treatment of uterine hypertension in pregnancy
The tactics of the patient’s management is determined by the degree of severity of the pathology. With a slight increase in tone, it is recommended to reduce physical and psychological stress, normalize sleep and rest, abandon spicy foods and spices. Pregnant women with moderate or pronounced tonic contraction of the myometrium, in addition to limiting activity, tocolytic therapy aimed at relaxing the uterus is indicated. In case of a disorder of the II degree, conservative treatment is carried out on an outpatient basis with the use of tablet forms of antispasmodics, in case of the III degree — inpatient with strict adherence to bed rest and mainly parenteral administration of medicines. To reduce the tone of the uterus , prescribe:
- Sedatives. Sedatives help to reduce anxiety, emotional tension, fear of losing a child, weaken alternative hotbeds of arousal, strengthen the dominant of pregnancy in the central nervous system. With moderately elevated tone, sedative herbal remedies are used, in severe condition, tranquilizers and even neuroleptics may be prescribed.
- Antispasmodics. Relaxation of smooth muscles is achieved by selectively inhibiting the activity of phosphodiesterase type IV and reducing intracellular calcium content. Antispasmodics effectively eliminate spasm of smooth muscle fibers of both nervous and muscular origin, enhance blood flow in tissues.
- Tocolytics. Beta-2-sympathomimetics activating adenylate cyclase are used for tocolytic purposes. As a result of increased cAMP synthesis, stimulation of the calcium pump, the concentration of calcium in myofibrils decreases, and the contractile activity of the uterus is inhibited. Magnesium sulfate is traditionally used to relax the myometrium (magnesium ions are competitors of calcium).
If the change in uterine tone is caused by progesterone deficiency, the patient is shown drugs with selective progestogenic action. Pregnancy in patients with increased contractile activity of the myometrium is recommended to be completed by natural childbirth in a physiological period. Caesarean section is performed only in the presence of obstetric indications (placental abruption, anatomically or clinically narrow pelvis, oblique or transverse position of the fetus, threat of rupture of the uterus, umbilical cord entanglement, etc.).
Prognosis and prevention
With 1-2 degrees of increased tone of uterine myofibrils, pregnancy usually proceeds without serious complications, with 3 degrees of disorder in the absence of adequate therapy, the prognosis worsens. When planning pregnancy, women suffering from gynecological diseases (endometritis, cervicitis, adnexitis, endometriosis, uterine fibroids) should take into account the opinion of an obstetrician-gynecologist, after the onset of gestation, early registration in a women’s consultation is recommended. For preventive purposes, pregnant women should reduce production, household loads, if necessary and possible, transfer to light work, observe a rest regime. At the moment of increasing the tone of the uterus, it is important to refrain from sexual contact.
