What is the management plan for a 17-week pregnant woman with newly diagnosed hypertension, who had normal blood pressure before pregnancy?

Management of New-Onset Hypertension at 17 Weeks Gestation

This patient has pre-existing (chronic) hypertension that was likely masked by the normal physiological blood pressure drop in early pregnancy, and requires immediate classification, proteinuria assessment, and consideration of antihypertensive therapy if blood pressure is ≥140/90 mmHg. 1

Immediate Classification and Diagnostic Workup

Confirm the diagnosis by repeating blood pressure measurements using proper technique with appropriate cuff size; if BP ≥160/110 mmHg, confirm within 15 minutes; if BP 140-159/90-109 mmHg, repeat over several hours. 2

Since hypertension is presenting before 20 weeks gestation, this is classified as pre-existing (chronic) hypertension, not gestational hypertension. 1, 2 The European Society of Cardiology specifically notes that undiagnosed hypertensive women may appear normotensive in early pregnancy due to the physiological BP fall in the first trimester, which masks pre-existing hypertension—exactly what has occurred in this case. 1

Obtain the following laboratory investigations immediately: 2

• Complete blood count with hemoglobin and platelet count
• Liver transaminases (AST, ALT)
• Serum creatinine
• Urinalysis with proteinuria assessment (24-hour urine collection or spot urine protein-to-creatinine ratio)

Proteinuria ≥0.3 g/day in 24-hour collection or ≥30 mg/mmol in spot urine would indicate superimposed preeclampsia, though this is uncommon before 20 weeks. 1, 2

Blood Pressure Thresholds for Treatment

Initiate antihypertensive medication if blood pressure is persistently ≥140/90 mmHg. 3 The European guidelines recommend treatment at BP ≥140/90 mmHg in women with pre-existing hypertension during pregnancy. 3

Target blood pressure should be 110-140/85 mmHg to reduce risk of severe hypertension without compromising uteroplacental perfusion. 2 This balances maternal protection against fetal safety, as excessively low blood pressure may impair placental perfusion. 1

First-Line Antihypertensive Medications

Methyldopa, labetalol, or nifedipine are the preferred first-line agents. 1, 2, 3 Methyldopa has the longest safety data with adequate infant follow-up (7.5 years), while labetalol has comparable efficacy. 1 Metoprolol is also acceptable. 1

Strictly avoid ACE inhibitors, ARBs, and direct renin inhibitors due to severe fetotoxicity, particularly in the second and third trimesters. 1, 4 If the patient was taking these medications before pregnancy recognition, switch immediately and arrange close fetal ultrasound monitoring. 1

Avoid atenolol as it is associated with fetal growth restriction when used long-term. 4

Non-Pharmacological Management

For blood pressure in the 140-150/90-99 mmHg range, consider initial non-pharmacological management with close supervision: 1

• Limitation of activities with some bed rest in left lateral position
• Normal diet without salt restriction (salt restriction may induce low intravascular volume, particularly near delivery)
• Calcium supplementation of at least 1 gram daily, which nearly halved the risk of preeclampsia in high-risk women 1

Do not recommend weight reduction during pregnancy in obese women, as it can lead to reduced neonatal weight and slower infant growth. 1

Aspirin Prophylaxis Timing

Low-dose aspirin (75-100 mg/day) should have been started before 16 weeks gestation in women with history of early-onset preeclampsia (<28 weeks). 1 At 17 weeks, this window has passed for this pregnancy, and aspirin is not indicated for routine pre-existing hypertension without prior preeclampsia history. 5

Monitoring and Follow-Up

Close supervision with frequent blood pressure monitoring is essential throughout pregnancy. 1 A short-term hospital stay may be required initially to confirm the diagnosis and rule out severe features. 1

Fetal ultrasound for biometry should begin at 26 weeks gestation if maternal uric acid is elevated or preeclampsia develops, with repeat ultrasound every 2-4 weeks if initial assessment is normal. 2

Indications for Immediate Hospital Assessment

Admit immediately if any of the following develop: 2, 4

• BP ≥160/110 mmHg (severe hypertension requiring treatment within 15 minutes)
• Development of proteinuria
• Severe headache, visual disturbances, or neurological symptoms
• Laboratory abnormalities suggesting preeclampsia (thrombocytopenia, elevated liver enzymes, rising creatinine)

Severe Hypertension Management

If BP reaches ≥160/110 mmHg, initiate urgent treatment within 15 minutes to 1 hour with IV labetalol, oral nifedipine, or IV hydralazine, targeting BP of 140-150/90-100 mmHg. 4, 6 Do not delay treatment waiting for laboratory results. 4

Delivery Timing

Delivery can be delayed until 39+6 weeks if: 2

• Blood pressure remains controlled
• Fetal monitoring is reassuring
• Preeclampsia has not developed

Deliver at ≥37 weeks if preeclampsia develops, with earlier delivery indicated for severe hypertension despite multiple antihypertensive agents, progressive thrombocytopenia, progressively abnormal liver/renal tests, pulmonary edema, severe neurological features, or non-reassuring fetal status. 2

Long-Term Cardiovascular Risk

Women with hypertensive disorders in pregnancy, particularly preeclampsia, are at significantly increased risk of developing cardiovascular disease later in life, including myocardial infarction, heart failure, stroke, and cardiovascular death. 7 Obstetric history should become part of lifelong cardiovascular risk assessment. 3, 7