High–Risk Pregnancy

High–risk pregnancy is a gestational process in which the probability of illness or death of the mother, fetus, newborn is higher than in the population. It can manifest itself by bleeding from the genital tract, signs of gestosis (edema, increased blood pressure) or proceed asymptomatically until the development of severe pathologies in a pregnant woman, newborn. The high risk of an unfavorable outcome is determined on the basis of anamnestic data, ultrasound results, blood tests, urine. Treatment is more often conservative, depending on the cause of the disorder.

ICD 10

O28 Abnormalities detected during antenatal examination of the mother

General information

High–risk pregnancy is characterized by an increased risk of an unfavorable outcome – premature termination, the birth of a sick or dead child, the development of severe pathology or the death of the mother before, during, and after childbirth. Its frequency is 70% among all pregnant women. The highest risk is observed in age-related (older than 35-40 years) mothers. The increase in the number of pathological pregnancies and childbirth is significantly influenced by the improvement of medical technologies (in particular IVF), which allow women who were previously considered infertile to conceive and bear a child.

Causes of high–risk pregnancy

The high risk is largely due to a decrease in the ability of the mother’s body to adapt to changes associated with the process of bearing a child. Most often, pathologies occur in women who had any disorders before gestation. Significant high-risk factors in pregnancy are:

• Extragenital pathologies in pregnant women. They cause an unfavorable outcome in 65% of women, most of them are due to congenital or acquired thrombophilia. Among others – diseases of the cardiovascular system, kidneys. Worsens the prognosis of diabetes mellitus of any type, disorders of the thyroid gland, adrenal glands.
• Features of the current gestation. The leading factors include fetoplacental insufficiency (31% of adverse outcomes), gestosis (20%), in vitro fertilization. Delayed (10%) and multiple (4%) pregnancies, pelvic presentation of the fetus (3.5%), isthmic-cervical insufficiency worsen the prognosis.
• Features of obstetric and gynecological anamnesis. Habitual miscarriage earlier with a high probability leads to premature termination of the current gestation. Early termination is often associated with ovarian insufficiency, immune pathologies, gynecological inflammations. Other causes of complications are artificial abortions, postoperative scar on the uterus.
• Common infections of a pregnant woman. The greatest danger to the baby in the womb is the so-called TORCH infections of the mother. The main ones include toxoplasmosis, viral infections (rubella, cytomegalovirus, herpes). Among others, bacterial (syphilis, tuberculosis, septic group infections), urogenital chlamydia, HIV infection.

Predisposing conditions for the occurrence of high risk are bad habits (alcohol abuse, smoking), occupational hazards (working with toxic substances, hard physical labor, prolonged psycho-emotional stress), hypovitaminosis (even with a balanced diet, pregnant women require additional intake of certain vitamins). The presence of malignant tumors fatally worsens the outcome of the gestational process.

Pathogenesis

Most of the factors adversely affecting the outcome of gestation have a causal relationship. In high-risk pregnancy, the unborn child is more likely to suffer. As a result of general somatic pathologies, endometritis and endometrial injuries during abortions, hyperandrogenism, the fetal egg is implanted insufficiently deeply, the development of the placenta is disrupted, which leads to fetoplacental insufficiency, slowing the development of the fetus, its loss.

Infections of the mother are transmitted through the placenta. Intrauterine infection before 4-6 months of pregnancy entails a high risk of organ malformations of the fetus, chronic hypoxia, interruption of the gestation process. Infection at a later date leads to congenital pathologies of normally formed organs (obstructive pulmonary disease, arthritis, osteomyelitis).

Post-term pregnancy is characterized by oxygen starvation of the child, causing damage to the central nervous system, a high risk of neurological disorders. Incorrect location leads to early rupture of the fetal bladder during childbirth, termination of progress along the birth canal, thinning of the walls of the uterus and poses a threat to both the child and the mother.

Gestosis, which often develops in pregnant women with extragenital pathology, is particularly dangerous for the life of the fetus and mother. The immune reaction and violation of the adaptive mechanisms of the female body to the fetal egg, the insufficiency of the spiral arteries that provide blood supply to the baby’s place, lead to placental hypoxia, the release of biologically active substances into the mother’s blood, vasospasm. As a result, the function of vital organs is disrupted.

Classification

To determine the pregnancy status, a table of risk factors is used, combined into several large groups, each of which corresponds to a certain number of points (from 1 to 20) – the higher the number, the higher the danger.

Among the potential adverse factors are socio–biological (height, weight and age indicators of the mother, occupational hazards, bad habits), pathologies of the patient (previously transferred or developed during this pregnancy), changes in the level of certain proteins, hormones in the blood serum. In the second half of gestation, the physical development and activity of the child are additionally assessed. The points received are summed up, the degree of risk is determined:

• Low – up to 4 points inclusive. A woman does not need regime restrictions.
• The average is 5-9 points. A pregnant woman may need a restrictive regime – at home or in a hospital.
• High – more than 9 points. The patient often needs a therapeutic and restrictive regime aimed at preserving pregnancy, periodic hospitalization, operative delivery.

There are more than 72 criteria for quantifying the danger. High–risk pregnancy may be due to one significant factor (for example, severe fetal hypertrophy – 2 points, eclampsia – 12, diabetes mellitus – 10) or several less significant ones (scar on the uterus – 4 points, age from 40 years – 4, obesity – 2).

Symptoms of high–risk pregnancy

High-risk pregnancy is often asymptomatic, especially with isolated lesions of the unborn baby. Of the external manifestations, there may be anointing, symptoms of toxicosis, gestosis, an increase in symptoms associated with somatic pathology. With cardiovascular diseases, this is shortness of breath, pallor, cyanosis, with kidney diseases – lower back pain, urination disorders, edema. Weakness, fatigue, drowsiness are often noted.

Early toxicosis is characteristic of the first trimester, manifested by salivation, repeated vomiting. More rare forms of toxicosis – jaundice, itching, convulsions of the muscles of the arms, legs, face (tetany of pregnant women) – can be observed at any gestation period. Gestosis develops from the 2nd trimester, accompanied by edema, arterial hypertension (dizziness, headache, feeling of “flies” in front of the eyes), seizures with loss of consciousness (eclampsia).

Complications

With any pathologies in a pregnant woman, the unborn child is most vulnerable. More than 50% of cases of childhood disability are associated with high-risk pregnancy. Disability is caused by delayed fetal development, intrauterine infection, hypoxia or trauma during childbirth. Premature birth – a frequent outcome of high-risk pregnancy – also often leads to disability, is the most common cause of neonatal (70%), infant (up to 65%) mortality.

In mothers, complications are more often associated with gestosis, aggravation of extragenital pathology, surgery on the uterus or incorrect fetal position (especially in out-of-hospital childbirth). The most severe of them include HELLP- and DIC-syndrome, massive uterine bleeding, multiple organ failure. These conditions often end in death, and the surviving women may have a significant decrease in the quality of life.

Diagnostics

Diagnostic measures provide for at least a three–time examination with the calculation of risk factors – up to 12 weeks (usually when registering in a women’s clinic), then at 30, 36-37 weeks. During pregnancy, the degree of danger may increase. The examination for the purpose of its assessment begins with the appointment of an obstetrician-gynecologist.

During the first appointment, an anamnesis is collected, a general obstetric examination is performed on the chair. The results are entered in the table, the pregnant woman is prescribed an instrumental, laboratory examination. The data of special research methods are also included in the calculation, sum up the risk indicator. Special research includes:

• Ultrasonography. Obstetric ultrasound allows you to assess the condition of the genitals, placenta, and baby. During the study, possible malformations, tumors of the internal genitals are identified, placental insufficiency is determined or predicted (according to the state of blood flow in the mother-placenta-fetus system), and the dynamics of the child’s development is evaluated.
• Electrophysiological methods. ECG is used to diagnose cardiac conduction disorders, ischemic heart lesions in the mother. Cardiotocography (CTG) is performed in late pregnancy to assess the condition of the fetus by its motor activity.
• Blood tests. To exclude anemia, a general blood test is performed. The results of the biochemical analysis indicate the functions of the kidneys and liver, the state of the hepatic parenchyma, iron deficiency. To diagnose thrombophilia, a coagulogram, tests for lupus anticoagulant and antibodies to phospholipids are performed.
• Analysis for proteins and hormones. It is carried out to identify anomalies of the child’s development. A marked increase in the fetal AFP protein in the mother’s blood makes it possible to suspect a neural tube defect, and its decrease in combination with an increase in beta-hCG is Down syndrome. An increase in the PAPP-A protein is a sign of fetal chromosomal abnormalities.
• Clinical analysis of urine. By the presence of protein in the urine, inflammatory kidney disease can be suspected. A decrease in density indicates chronic renal failure, diabetes insipidus. The study of sediment contributes to the diagnosis of organic lesions, inflammation of the urinary organs.
• Research on infections. To detect common infections, a serological blood test is performed for the TORCH complex and syphilis. The material from the vagina (smears and scrapings) is examined by the cultural method (to detect non-specific infection of the genitals), using PCR (sexually transmitted diseases are diagnosed).

If necessary, ultrasound or MRI of the kidneys, liver, and echocardiography are performed. If extragenital pathologies are suspected, a consultation with a nephrologist, cardiologist, rheumatologist may be required.

Treatment

Most often, when a high–risk pregnancy is detected, conservative treatment is prescribed – drug therapy. With the threat of premature birth, deterioration of the mother’s condition, a protective regime is prescribed. The use of surgical treatment may be required in case of cervical failure, some tumors of the genitals, the need for surgical delivery.

Conservative therapy

Compliance with the protective regime is an important condition for maintaining a high–risk pregnancy. Strict bed rest is prescribed in a hospital with gestosis, pronounced extragenital pathology. To observe a semi-bed rest (including at home) is sometimes required throughout the entire gestation period (for example, with cervical insufficiency after trachelectomy).

Treatment is carried out under the guidance of an obstetrician-gynecologist, narrow specialists are involved as necessary. In the presence of general somatic diseases, the correction of disorders depends on the lesion of a particular organ or system. Conservative treatment of the most common pathologies:

• Gestosis. Infusion therapy with colloidal and saline solutions is prescribed. Sedative effect is provided by tranquilizers. Hypotensive and vasodilating drugs are used to reduce blood pressure. With gestosis against the background of kidney and heart diseases, diuretics are used. With the development of eclampsia, treatment is supplemented with ganglioblockers, narcotic and psychotropic drugs.
• Fetoplacental insufficiency. In order to improve blood supply to the placenta, vasodilators and antispasmodics, heparin, are prescribed. B-adrenomimetics, hormones (estrogens, progestogens), cardiac glycosides are used. Colloidal solutions are infused, hyperbaric oxygenation is performed. Amino acids are used to activate metabolic processes.
• Infections. In bacterial, chlamydial, toxoplasma infections, antibiotics, sulfonamide and antiprotozoal drugs are used. Infectious foci (colpitis, cervicitis, tonsillitis) are sanitized. In viral diseases, gamma globulins are injected. In the case of HIV infection, antiretroviral therapy is carried out.

Surgical treatment

Surgical operations during high–risk pregnancy are rarely performed: surgical intervention is not required to eliminate most of the causes of high-risk pregnancy, and the operation itself may be an additional factor in an unfavorable outcome. Types of surgical treatment most commonly used during pregnancy and childbirth:

• Cervical cerclage. Suturing of the cervix. The procedure is carried out in the early stages of pregnancy in order to prevent its early termination in case of isthmic-cervical insufficiency. The operation is indicated for functional disorders and organic lesions of the cervix, if conservative methods do not give results.
• Removal of tumors. Excision of neoplasms during pregnancy is most often prescribed for benign neoplasia of the ovary and myomatous nodes with signs of inflammation or necrosis. In malignant tumors, resection is possible only in the case of non-invasive and microinvasive cancer.
• Caesarean section. Fetal extraction through an incision of the abdominal wall and the body of the uterus. They are performed for early or urgent delivery. Early childbirth is resorted to to preserve the life of the mother and child with a progressive pathology of pregnancy or a general somatic disease. Urgent delivery by surgery is indicated if natural vaginal delivery is not recommended.

Prognosis and prevention

The prognosis of high–risk pregnancy depends on the severity of predisposing factors, the timing of their detection, and the possibility of elimination. Early diagnosis with the use of modern equipment, immediate treatment of pregnant women have reduced the rates of stillbirth and mortality in the first year of life by almost 40% over the past 20 years. An important role in preventing a high risk of pregnancy is assigned to pregravidar preparation.

Preventive measures include rational protection against unwanted conception, timely diagnosis and treatment of pathologies that entail the danger of high perinatal and obstetric risk, a healthy lifestyle (this also applies to the future father). At the planning stage, the body weight should be normalized. Pregnancy should not be postponed until too late in life. Secondary prevention involves dispensary observation during gestation.