What is the diagnosis and management of Pregnancy-Induced Hypertension (PIH)?

From the Guidelines

Pregnancy-induced hypertension (PIH) should be managed with immediate drug treatment for blood pressure >160/110 mmHg, using labetalol or nifedipine as first-line treatment, and delivery is the definitive treatment, particularly after 37 weeks or in severe cases. PIH is a condition characterized by high blood pressure that develops after 20 weeks of pregnancy in women who previously had normal blood pressure, affecting 5-10% of pregnancies and including gestational hypertension, preeclampsia, and eclampsia [ 1 ]. For management, regular prenatal care with blood pressure monitoring is essential. Mild cases may be managed with rest and close monitoring, while severe cases require antihypertensive medications.

Diagnosis and Management

• Blood pressure monitoring is crucial in diagnosing and managing PIH, with severe hypertension (≥160/110 mmHg) requiring immediate treatment [ 1 ].
• First-line medications for PIH include labetalol (starting at 100-400 mg orally twice daily) and nifedipine (10-20 mg orally every 4-6 hours) [ 1 ].
• Magnesium sulfate is used to prevent seizures in severe preeclampsia, typically as a 4-6g IV loading dose followed by 1-2g/hour maintenance [ 1 ].
• Delivery is the definitive treatment, particularly after 37 weeks or in severe cases, and women with preeclampsia should be delivered if they have reached 37 weeks’ gestation or develop any severe complications [ 1 ].

Complications and Monitoring

• PIH requires close monitoring for complications including placental abruption, HELLP syndrome, and fetal growth restriction [ 1 ].
• Women with a history of PIH should be monitored closely in subsequent pregnancies as they have an increased risk of recurrence and future cardiovascular disease [ 1 ].
• Maternal monitoring in preeclampsia should include BP monitoring, repeated assessments for proteinuria, clinical assessment, and twice weekly blood tests for hemoglobin, platelet count, liver transaminases, creatinine, and uric acid [ 1 ].

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Diagnosis of Pregnancy-Induced Hypertension (PIH)

• PIH is defined as systolic blood pressure (SBP) >140 mmHg and diastolic blood pressure (DBP) >90 mmHg 2
• It is classified as mild (SBP 140-149 and DBP 90-99 mmHg), moderate (SBP 150-159 and DBP 100-109 mmHg) and severe (SBP ≥ 160 and DBP ≥ 110 mmHg) 2
• PIH refers to one of four conditions: a) pre-existing hypertension, b) gestational hypertension and preeclampsia (PE), c) pre-existing hypertension plus superimposed gestational hypertension with proteinuria and d) unclassifiable hypertension 2

Management of PIH

• Non-drug management is recommended when SBP ranges between 140-149 mmHg or DBP between 90-99 mmHg 2
• Antihypertensive treatment is recommended in pregnancy when blood pressure levels are ≥ 150/95 mmHg according to 2013 ESH/ESC guidelines 2
• Initiation of antihypertensive treatment at values ≥ 140/90 mmHg is recommended in women with a) gestational hypertension, with or without proteinuria, b) pre-existing hypertension with the superimposition of gestational hypertension or c) hypertension with asymptomatic organ damage or symptoms at any time during pregnancy 2
• Methyldopa is the drug of choice in pregnancy, while Atenolol and metoprolol appear to be safe and effective in late pregnancy, and labetalol has an efficacy comparable to methyldopa 2, 3
• Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II antagonists are contraindicated in pregnancy due to their association with increased risk of fetopathy 2, 3

Treatment of Severe Hypertension

• Severe hypertension >160/110 mmHg may require parenteral therapy, and treatment with intravenous labetalol now supplants the use of hydralazine 3
• First-line intravenous drugs include labetalol and hydralazine, but other agents may be used, including esmolol, nicardipine, nifedipine, and, as a last resort, sodium nitroprusside 4
• The goal of treatment is to reduce blood pressure to a systolic blood pressure between 140 mmHg and 150 mmHg and diastolic pressure between 90 mmHg and 100 mmHg 4

Long-Term Risks

• Hypertensive disorders of pregnancy are emerging as risk factors for future cardiovascular risk 3, 5
• Women with chronic hypertension should undergo a prepregnancy evaluation and close monitoring during and after pregnancy to ensure medication safety and to prevent end-organ damage 5
• Hypertensive complications during pregnancy are potentially linked to cardiovascular, kidney, and metabolic diseases later in life 5