What is the management of pregnancy-induced hypertension?

Management of Pregnancy-Induced Hypertension

The management of pregnancy-induced hypertension requires prompt recognition, classification, and appropriate treatment based on severity, with medication initiation recommended at BP ≥140/90 mmHg for women with gestational hypertension, pre-existing hypertension with superimposed gestational hypertension, or hypertension with subclinical organ damage. 1, 2

Classification of Hypertensive Disorders in Pregnancy

• Hypertension in pregnancy is classified into four categories: pre-existing hypertension, gestational hypertension, pre-existing hypertension plus superimposed gestational hypertension with proteinuria, and antenatally unclassifiable hypertension 3
• Pre-existing hypertension complicates 1-5% of pregnancies and is defined as BP ≥140/90 mmHg that precedes pregnancy or develops before 20 weeks of gestation 3
• Gestational hypertension is pregnancy-induced hypertension that develops after 20 weeks of gestation, with or without proteinuria, and complicates 6-7% of pregnancies 3
• Pre-eclampsia is defined as gestational hypertension with clinically significant proteinuria (≥0.3 g/day in a 24h urine collection or ≥30 mg/mmol urinary creatinine) 3, 1

Treatment Thresholds and Targets

• Initiate drug treatment in women with gestational hypertension, pre-existing hypertension with superimposed gestational hypertension, or hypertension with subclinical organ damage at BP ≥140/90 mmHg 3, 2
• For all other pregnant women with hypertension, initiate treatment at BP ≥150/95 mmHg 3, 2
• Target BP should be below 140/90 mmHg but not below 80 mmHg for diastolic BP to ensure adequate uteroplacental perfusion 2
• Severe hypertension (SBP ≥170 mmHg or DBP ≥110 mmHg) is considered an emergency requiring immediate hospitalization 3, 2

Non-Pharmacological Management

• Consider non-pharmacological management for pregnant women with SBP of 140-150 mmHg or DBP of 90-99 mmHg 3, 2
• Management includes close supervision, limitation of activities, and some bed rest in the left lateral position 3, 2
• Maintain a normal diet without salt restriction, particularly close to delivery, as salt restriction may induce low intravascular volume 3, 2
• For high-risk women with a history of early-onset pre-eclampsia (<28 weeks), administer low-dose acetylsalicylic acid (75-100 mg/day) prophylactically at bedtime, starting before 16 weeks gestation 3, 2

Pharmacological Management

First-line Medications

• Methyldopa is the drug of choice with the longest safety record and adequate infant follow-up (7.5 years) 3, 1, 4
• Labetalol has efficacy comparable to methyldopa and can be given intravenously for severe hypertension 3, 1, 5
• Nifedipine (extended-release) is also recommended as a first-line agent 1, 2

Second-line Medications

• Hydralazine and prazosin can be used as second or third-line agents 1
• Metoprolol is also recommended, particularly in late pregnancy 6

Contraindicated Medications

• ACE inhibitors, ARBs, and direct renin inhibitors are strictly contraindicated throughout pregnancy due to severe fetotoxicity, particularly in the second and third trimesters 3, 6

Management of Severe Hypertension

• Urgent treatment in a monitored setting is required for BP ≥170/110 mmHg 3, 2
• First-line agents for severe hypertension include IV labetalol, oral nifedipine, and IV hydralazine 1, 2
• For severe hypertension associated with pulmonary edema, nitroglycerine (glyceryl trinitrate) can be given as an IV infusion 3

Delivery Considerations

• Induction of delivery is indicated in gestational hypertension with proteinuria when adverse conditions are present, such as visual disturbances, coagulation abnormalities, or fetal distress 3, 1
• The European Society of Cardiology recommends delivering women with pre-eclampsia at 37 weeks gestation 1

Postpartum Management

• Hypertension is common post-partum, with BP usually rising after delivery over the first 5 days 3
• Avoid methyldopa post-partum due to the risk of post-natal depression 3
• Continue antihypertensive medications postpartum with gradual tapering rather than abrupt cessation 2
• Safe antihypertensive medications for breastfeeding mothers include labetalol, nifedipine, and beta-blockers 2

Long-term Considerations

• Women who develop gestational hypertension or pre-eclampsia have an increased risk of hypertension, stroke, and ischemic heart disease in later life 3, 1
• The relative risk of developing ischemic heart disease after pre-eclampsia is more than twice as high compared with women with normal pregnancies 3
• Lifestyle modifications, regular BP monitoring, and control of metabolic factors are recommended after delivery to reduce future cardiovascular risk 3, 2
• Annual medical review is recommended lifelong for women who had hypertensive disorders of pregnancy 2

Special Considerations

• Women with early-onset pre-eclampsia (delivery before 32 weeks), stillbirth, or fetal growth retardation are at highest risk for future cardiovascular disease 3
• Risk factors for hypertensive disorders before pregnancy include high maternal age, elevated BP, dyslipidemia, obesity, positive family history, antiphospholipid syndrome, and glucose intolerance 3
• Women experiencing hypertension in their first pregnancy are at increased risk in subsequent pregnancies 3