Hypertension specialist Dr. Tarek Antonios outlines how to manage patients at risk for hypertensive complications during pregnancy
Hypertension, including during pregnancy, is diagnosed when office blood pressure is consistently above 140/90 mmHg (measured several times over 2-4 weeks). Diagnosis should be confirmed by either 24-hour ambulatory blood pressure monitoring or home monitoring. High blood pressure is confirmed if the reading is above 135/85 mmHg.
Hypertensive disorders of pregnancy (HDP) affect approximately 10% of pregnancies worldwide and are an important cause of maternal, fetal, and neonatal morbidity and mortality. HDP also increases the risk of future cardiovascular disease not only in the mother, but also in the offspring later in life.
HDP incorporates all forms of hypertension during pregnancy defined by systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg (see Box 1). Hypertension can be mild (between 140/90mmHg and 159/99mmHg) or severe (160/100mmHg or higher).
Chronic hypertension is defined as hypertension present before pregnancy or first diagnosed before 20 weeks of gestation.
Gestational hypertension, or pregnancy-induced hypertension, is new-onset hypertension diagnosed after 20 weeks of gestation and without proteinuria that resolves within 3 months of birth.
Box 1: HDP types
- Chronic hypertension (may be secondary to underlying disease)
- Gestational hypertension (pregnancy-induced)
- Pre-eclampsia with chronic hypertension
Preeclampsia or toxemia of pregnancy is defined as new-onset hypertension after 20 weeks of gestation, with either proteinuria (urine PCR ≥30 mg/mmol, or ACR ≥8 mg/mmol, or dipstick test 2+). or maternal organ dysfunction (increased serum creatinine, elevated liver enzymes, persistent headache, visual disturbances, low platelet count, microangiopathic hemolytic anemia) or uteroplacental dysfunction (fetal growth restriction) , abnormal umbilical artery Doppler, or stillbirth).
Risk factors for pre-eclampsia
Pre-eclampsia has several risk factors, including:
- chronic hypertension
- hypertension in previous pregnancies
- chronic kidney disease
- systemic lupus erythematosus
- antiphospholipid syndrome
- type 1 or type 2 diabetes;
- Age 40+
- Pregnancy interval of 10 years or more
- – Obese with a BMI ≥ 35 at the first prenatal visit
- Family history of preeclampsia
- Multiple pregnancy.
Women at risk of developing pre-eclampsia are advised to take 75-150 mg of aspirin daily from 12 weeks of pregnancy until delivery to prevent pre-eclampsia. The protective effect of aspirin in pre-eclampsia is not understood.
Box 2: Blood pressure measurement during pregnancy
- Pregnant women should sit with their legs supported for 2-3 minutes.
- Appropriately sized cuffs should be used. The cuff bladder should enclose at least 80% of the arm.
- Systolic blood pressure is palpated at the brachial artery and the cuff is inflated to 20 mmHg above this level. The cuff should deflate slowly at approximately 2mmHg/sec.
- Diastolic blood pressure should be recorded as Korotkoff phase 5 (vanishing). Phase 4 (Mute) should only be used if Phase 5 is not present.
Prenatal care for patients at risk for HDP
NICE recommends that women with pre-existing (chronic) hypertension who are of childbearing potential are offered a referral to a hypertension specialist to discuss treatment. ACE inhibitors and ARBs should not be prescribed to women with hypertension who are at risk of pregnancy and should be discontinued if the woman becomes pregnant as these drugs increase the risk of birth defects. In addition, thiazides and thiazide-like diuretics are associated with an increased risk of birth defects and should be avoided if possible.Non-pharmacological management of HDP should follow usual lifestyle advice for chronic hypertension. there is.
Pharmacological treatment of HDP
If systolic blood pressure remains above 140 mmHg or diastolic blood pressure remains above 90 mmHg, the following drugs are recommended for the treatment of HDP:
- Labeta roll.
- Nifedipine (if labetalol is not tolerated).
- Methyldopa (if both labetalol and nifedipine are intolerable).
The goal of treatment is to bring blood pressure below 135/85 mmHg.
Exclusion of secondary causes of hypertension
The majority of hypertensive patients are diagnosed with primary (essential) hypertension because no identifiable cause of hypertension is found. However, in his 10-20% of subjects, a secondary and treatable cause may be found. Box 3 summarizes common causes of secondary hypertension. Secondary hypertension is defined in patients <40 years of age, severe or resistant hypertension, biochemical abnormalities (hypokalemia, hypercalcemia, metabolic alkalosis) or suspicious symptoms (excessive sweating, palpitations, panic Underscoring that undiagnosed secondary hypertension in pregnant women can pose significant risks if not managed is important.
For example, fibromuscular dysplasia (FMD) renal artery stenosis is the most common cause of severe or resistant hypertension in young women. FMD can be associated with renal aneurysms that can rupture during pregnancy and cause devastating internal bleeding. Similarly, pheochromocytoma, although very rare, carries a risk of mortality as high as 58% for both mother and fetus if not treated. Women with suspected secondary hypertension can be diagnosed and treated before conception. As such, a referral to a hypertension specialist is required.
Box 3: Secondary causes of hypertension
- Hyperaldosteronism (adrenal hyperplasia, adrenal adenoma)
- Cushing’s syndrome
- thyroid and parathyroid disease
- Renal artery stenosis (fibromuscular dysplasia)
- Renal parenchymal disease (glomerulonephritis, connective tissue disease, polycystic kidney disease)
- Post kidney transplant
Postnatal blood pressure monitoring
Women with HDP may require antihypertensive therapy in the postpartum period. NICE recommends that blood pressure be measured daily for her first two days after birth, and then at least once between her third day and her fifth day. The goal is to keep her blood pressure below her 140/90mmHg. If methyldopa is used to treat chronic hypertension during pregnancy, it should be changed to another treatment by the second day of life.
In my practice, I advise women with a history of HDP to invest in a home BP machine and monitor it regularly. If your home blood pressure drops or you feel dizzy during treatment, you should reconsider in primary care.A woman who cannot invest in a home BP machine should be considered in primary her care if she is 1-2 You should be tested every month.
Breastfeeding while taking antihypertensive drugs
Most antihypertensive drugs have not been tested in pregnant or lactating women and appear at very low levels in breast milk, making them unlikely to have significant clinical efficacy. We recommend that you monitor your baby for lethargy, pallor, chilly surroundings, or poor feeding and seek further help.
NICE guidelines recommend giving enalapril tablets to treat postpartum hypertension while monitoring maternal renal function and potassium. but not ARBs or diuretics.
Women with chronic hypertension who do not intend to breastfeed can quickly revert to their pre-pregnancy antihypertensive medications.
Long-term monitoring of women with a history of HDP
As previously mentioned, HDP increases the risk of death from hypertension and cardiovascular disease not only in the affected mother, but also in subsequent children. Most CVD guidelines consider HDP to be an independent risk factor for her CVD in the future and recommend that these women undergo annual follow-up. The overall risk of HDP in future pregnancies is estimated to be her 1 in 5. A woman with a history of HDP should make lifestyle modifications to reduce her CVD risk in the future.
- Hypertension of pregnancy (HDP) affects approximately 10% of pregnancies worldwide and is an important cause of maternal, fetal, and neonatal morbidity and mortality.
- The term HDP includes all forms of hypertension that occur during pregnancy. These include pre-existing (chronic) hypertension, gestational hypertension and pre-eclampsia.
- HDP increases the risk of future cardiovascular disease not only in affected mothers but also in their offspring
- People with pre-existing (chronic) hypertension should be referred to a specialist for counseling about the benefits and risks of treatment
- Individuals should discontinue treatment with ACE inhibitors or ARBs within 2 days of notification of pregnancy and offer alternative treatment.People taking thiazides or thiazide-like diuretics should be informed of the risks and offered alternative treatments
- HDP should be treated with (in order of preference) labetalol, nifedipine, or methyldopa.Target blood pressure is 135/85mmHg or less
Dr. Tarek Antonios is a Senior Lecturer and Consulting Physician in Cardiovascular and General Medicine and Head of the Blood Pressure Division at St George’s University Hospital NHS Trust, London.
- good. NG 133. Hypertension in Pregnancy: Diagnosis and Management.Link
- Webster K, Fishburn S, Maresh M et al. Diagnosis and management of hypertension during pregnancy: an updated NICE guidance summary. BMJMore 2019;366:l5119.Link