What is the best advice for a female of childbearing age with chronic hypertension (high blood pressure) and a current blood pressure of hypertension, who is planning to conceive and is currently managing her condition with lifestyle modifications?

Preconception Management of Chronic Hypertension

Start antihypertensive medication immediately to achieve blood pressure control before conception, as a BP of 150 systolic significantly increases maternal and fetal risks during pregnancy. 1

Rationale for Immediate Pharmacological Treatment

Your patient's systolic blood pressure of 150 mmHg meets the threshold for initiating antihypertensive therapy in the preconception period. While guidelines traditionally recommend treatment at 150-160/100-110 mmHg, treatment should be reinstituted once BP reaches 150 to 160 mm Hg systolic or 100 to 110 mm Hg diastolic, in order to prevent increases in BP to very high levels during pregnancy. 1

• Poorly-controlled hypertension in the first trimester significantly increases maternal and fetal morbidity and mortality. 2
• Women with chronic hypertension face a 25% risk of developing superimposed preeclampsia during pregnancy, with outcomes directly related to the degree of hypertension control. 1
• Chronic hypertension in pregnancy is associated with higher rates of preterm birth, placental abruption, intrauterine growth restriction, and fetal death. 1

Recommended First-Line Medications

Extended-release nifedipine is the preferred first-line agent for women planning pregnancy, with the strongest safety data and the advantage of once-daily dosing to improve adherence. 3, 4

Alternative first-line options include:

• Labetalol serves as an excellent alternative, particularly for women without reactive airway disease (contraindicated in asthma). 3, 4
• Methyldopa has the longest safety record with long-term infant outcome data, though it should be used cautiously in women at risk for depression and must be switched postnatally. 1, 3

Blood Pressure Targets

Target BP should be <140/90 mmHg but not below 80 mmHg diastolic to balance maternal cardiovascular protection with adequate uteroplacental perfusion. 4

• During pregnancy, aim for 110-135/85 mmHg to minimize both maternal complications and impairment of fetal growth. 3, 4
• Treatment at these levels reduces the risk of accelerated maternal hypertension while minimizing fetal growth restriction. 3

Essential Preconception Assessments

Before conception, the following evaluations are critical:

• Complete blood count, liver enzymes, serum creatinine, electrolytes, uric acid, and urinalysis with protein-to-creatinine ratio to establish baseline values for detecting superimposed preeclampsia later. 1
• Screen for secondary causes of hypertension (renal parenchymal disease, fibromuscular hyperplasia, primary hyperaldosteronism) if clinically indicated, particularly in women diagnosed before age 40. 1, 4
• Assess for target organ damage including retinopathy, renal disease, and ventricular hypertrophy in women with long-standing hypertension. 1

Additional Preconception Interventions

Low-dose aspirin (75-150 mg daily) should be started at bedtime immediately upon initiating preconception planning, but before 16 weeks gestation, to reduce the risk of preeclampsia. 4

Lifestyle modifications remain important adjuncts:

• Sodium restriction to 2.4 g daily is recommended, though weight reduction should not be attempted during pregnancy itself. 1
• Moderate physical activity should continue, though aerobic exercise may need restriction during pregnancy based on theoretical concerns about placental blood flow. 1

Critical Pitfalls to Avoid

Never delay conception unnecessarily - the goal is to achieve BP control while planning pregnancy, not to postpone pregnancy indefinitely. 1

• Continuing lifestyle modification alone is inadequate at this BP level, as there is no evidence that delaying pharmacological treatment improves outcomes, and uncontrolled hypertension poses immediate risks. 1
• Avoid ACE inhibitors, ARBs, direct renin inhibitors, and mineralocorticoid receptor antagonists entirely, as these are absolutely contraindicated due to fetal teratogenicity and oligohydramnios. 1, 3, 4
• Diuretics should generally be avoided during pregnancy planning due to risk of reducing uteroplacental perfusion, though they are probably safe if already established. 1, 4
• Atenolol should be avoided as it is associated with intrauterine growth restriction. 1, 5

Monitoring Strategy

• Confirm hypertension diagnosis with home BP monitoring or 24-hour ambulatory monitoring before long-term treatment, as up to 25% of elevated clinic readings represent white-coat hypertension. 1, 4
• Continue regular BP monitoring throughout the preconception period and pregnancy. 4
• Educate the patient that BP typically falls during the first half of pregnancy, potentially allowing medication reduction, but close monitoring remains essential. 1

Long-Term Considerations

Women with hypertension during pregnancy have increased cardiovascular disease risk later in life, requiring annual cardiovascular risk assessment lifelong. 4