Hypertension during Pregnancy (ICD-10: O13)

Disease Definition and Causes

Hypertension during pregnancy refers to an increase in arterial blood pressure (systolic), recorded twice or more within four hours. Readings surpassing 140 mmHg for systolic pressure and 90 mmHg for diastolic pressure are considered elevated.

• Hypertension may occur due to primary (essential) hypertension or secondary symptomatic hypertension.
• Primary hypertension is not caused by a single factor but is a multifactorial disease resulting from genetic and acquired factors. Acquired factors include repeated stressful conditions, excessive salt consumption, diabetes, obesity, elevated blood lipids, limited physical activity, and smoking.
  Secondary hypertension typically has a single cause for elevated blood pressure, such as kidney or renal vascular diseases, adrenal gland disorders, neurological diseases, among others. While pregnancy is not a direct cause of primary or secondary hypertension, significant pressure on the cardiovascular system during pregnancy, childbirth, and postpartum period may contribute to the detection or exacerbation of pre-existing cardiac and vascular issues in women’s bodies.

Symptoms of Hypertension during Pregnancy:
Symptoms of arterial hypertension during pregnancy without specific complications include:

• Headache
• Increased heart rate
• Nausea
• Shortness of breath
• Weakness
  These symptoms may also be observed in other conditions unrelated to hypertension, as well as during normal pregnancy.

Complications of hypertension may manifest symptoms from targeted organs:

• Heart: Arrhythmias, chest pain, shortness of breath, and swelling.
• Brain: Decline in cognitive abilities, dizziness, neurological disorders.
• Eyes: Vision disturbances, even blindness.
• Peripheral arteries: Coldness in extremities, intermittent paralysis.
• Kidneys: Nocturia, swelling.
  Additionally, serious complications related to microvascular blood vessels may occur during pregnancy. These complications include hypertensive disorders of pregnancy and eclampsia. Hypertensive disorders of pregnancy may be asymptomatic except for elevated blood pressure and proteinuria, but may manifest with nonspecific symptoms from various organs and systems. Regarding eclampsia, it presents with seizures accompanied by loss of consciousness.

Classification and Stages of Hypertension during Pregnancy:
Based on time of detection:

• Chronic hypertension: Detected before pregnancy or within the first 20 weeks of pregnancy, divided into primary and secondary hypertension.
• Gestational hypertension: Detected after 20 weeks of pregnancy.
• Chronic hypertension with superimposed preeclampsia syndrome: Chronic hypertension with proteinuria ≥ 3 grams/liter.

Classification specific to pregnant women for the degree of high blood pressure is determined based on the highest level of systolic (upper) or diastolic (lower) blood pressure:

• Normal blood pressure: Systolic < 140 and diastolic < 90.
• Mild hypertension: Systolic 140-159 and/or diastolic 90-109.
• Severe hypertension: Systolic ≥ 160 and/or diastolic ≥ 110.

Stages depend on the presence of complications:

• Stage 1: No complications present.
• Stage 2: Changes occur in one or more targeted organs (heart, blood vessels, brain, eyes, kidneys).
• Stage 3: Clinical conditions are present, indicating significant structural abnormalities in targeted organs (heart attack, chest pain, stroke, kidney failure, retinal hemorrhage, optic nerve swelling).

Complications of hypertension during pregnancy include:

• Placental insufficiency: Inability to provide adequate blood and nutrients to the fetus.
• Intrauterine growth restriction syndrome: Fetal growth delay due to poor blood circulation.
• Intrauterine fetal demise: Fetal death during pregnancy.
• Early neonatal death: Death of the child shortly after birth.
• Premature placental abruption: Premature detachment of the placenta from the uterine wall.
• Antepartum or intrapartum hemorrhage: Significant blood loss during childbirth.
• Eclampsia syndrome: A condition involving seizures and loss of consciousness.
• Serious disturbances in the blood clotting system: Serious problems in blood clotting.
• Acute kidney injury: Severe kidney damage due to high blood pressure.
• Pulmonary edema: Fluid accumulation in the lungs.
• Retinal hemorrhage and detachment: Bleeding or detachment of the retina.
• Stroke: Sudden cessation of blood flow to a part of the brain.

Diagnosis of hypertension during pregnancy involves:

• Determining the degree of high blood pressure.
• Assessing the condition of targeted organs.
• Identifying the risk of developing preeclampsia syndrome.
• Evaluating the effectiveness of received treatment.

Specialists to consult include obstetricians/gynecologists, internists (cardiologists), neurologists, ophthalmologists, and endocrinologists.

Physical examination involves:

• Measuring blood pressure as the primary diagnostic method. Blood pressure should be measured separately on each arm, preferably after a prior rest of 5-10 minutes. The correct reading is the higher blood pressure reading. Approximately 1.5-2 hours of rest after eating is recommended. For more accurate results, it is preferable to avoid drinking coffee and tea on the day of diagnosis.

Laboratory Diagnosis:

• Urine analysis is conducted to assess overall health and detect any potential changes.
• Blood component examination is performed to evaluate general health, and changes in blood condition may be revealed.
• Hematocrit measurement is used to assess the ratio of red blood cell volume to fluid volume in the blood.
• It is carried out to evaluate liver and kidney function and may play a role in monitoring the impact of hypertension.

Detection of Preeclampsia:

• All pregnant women should be screened for protein in urine (proteinuria) in early stages. If the test strip result is ≥1, further tests should be performed immediately, such as determining the albumin-to-creatinine ratio in a urine sample.

Radiological Diagnosis:

• Electrocardiography
• Fundus examination for retinal vessels
• Ultrasound imaging: Used to evaluate the heart and uterine arteries at week 20 of pregnancy.
• Ultrasound imaging of the adrenal glands: Conducted to assess the adrenal glands.

Criteria for Preeclampsia Diagnosis (PE):

• Preeclampsia typically occurs after week 20 of pregnancy and includes hypertension and proteinuria (≥ 0.3 g/day).
• Eclampsia: Seizures occur suddenly in women with preeclampsia.

Treatment of Hypertension during Pregnancy:
Objectives of hypertension treatment in pregnant women:

1. Prevention of complications associated with hypertension.
2. Maintenance of pregnancy.
3. Normal fetal development and timely delivery.

There are two methods of hypertension treatment during pregnancy:
Outpatient treatment:

• Improving lifestyle and nutrition.
• Smoking cessation.
• Following a balanced diet.
• Moderate physical activity.
• Daily outdoor exercise.
• Ensuring an adequate rest period.

In-hospital treatment:

• Required when there is:
• Pregnancy-induced hypertension (≥ 140/90 after week 20 of pregnancy).
• Hypertensive crisis (rapid increase in blood pressure ≥ 170/110).
• Preeclampsia (hypertension ≥ 140/90 + presence of protein in urine).
• Eclampsia (seizures).

Drug Therapy:
Indications for initiating medication:

• In women with chronic uncomplicated hypertension: systolic blood pressure ≥ 150 and/or diastolic blood pressure ≥ 95.
• In all other cases (pregnancy-induced hypertension, preeclampsia, target organ damage, associated clinical conditions), systolic blood pressure ≥ 140 and/or diastolic blood pressure ≥ 90 mmHg.

Important aspects of drug treatment:

• Drug selection depends on the stage of pregnancy, with significant restrictions in the first trimester and postpartum period, based on the presence or absence of breastfeeding.
• Treatment begins with small doses of a single drug (usually methyldopa), and if necessary, the dose is increased and another drug is added.
• Target blood pressure should be maintained for 24 hours, so blood pressure should be monitored regularly even if feeling well to ensure timely adjustment of treatment.
• Hypertension itself is not a barrier to natural childbirth, but drug treatment should continue during childbirth.

Treatment of Low Blood Pressure in Pregnant Women: Methyldopa and Beta-blockers:

• Methyldopa (1000 to 3000 mg daily) is preferred.
• In case of threatened preeclampsia, nifedipine is used at a dose of up to 40 mg daily, in addition to beta-blockers (often labetalol, with metoprolol succinate being among the options).

List of Prohibited Medications:

• Renin-angiotensin-aldosterone system inhibitors (angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, direct renin inhibitors) are prohibited.

List of Allowed Medications:

• Methyldopa.
• Selective beta-blockers.
• Nifedipine.

Medical Care Plan for Eclampsia (Seizures):

• Hypertension and preeclampsia are treated in the obstetrics department, where magnesium sulfate injections are used intravenously to control convulsions, in addition to using nitroprusside 1% and other drugs according to the patient’s condition and specific tests.

Sources:

1. Russian Cardiological Society’s publication on the Diagnosis and Treatment of Cardiovascular Diseases during Pregnancy in 2018, as per National Recommendations, published in the Russian Cardiological Journal, 2018, No. 3 (155), pages 91-134.
2. Russian Cardiological Society’s 2013 publication on the Diagnosis and Treatment of Cardiovascular Diseases during Pregnancy, featuring Russian Recommendations, found in the Russian Cardiological Journal, 2013, No. 4 (102), spanning 40 pages.
3. Fourth Revision of Recommendations on Diagnosis and Treatment by the Russian Cardiological Society in 2010, documented in the journal “Systemic Hypertension,” 2010, No. 3, covering pages 5-26.