What is the management for blood pressure (BP) control in preeclampsia?

From the Guidelines

Blood pressure control in preeclampsia requires urgent treatment with acceptable agents including oral nifedipine or intravenous labetalol or hydralazine when severe (>160/110 mm Hg), and treatment should be aimed at a target diastolic BP of 85 mm Hg (and systolic BP of 110–140 mm Hg) to reduce the likelihood of developing severe maternal hypertension and other complications. According to the ISSHP classification, diagnosis, and management recommendations for international practice 1, women with preeclampsia should be assessed in hospital when first diagnosed, and thereafter, some may be managed as outpatients once it is established that their condition is stable.

Key Management Points

• Urgent treatment is required when blood pressure exceeds 160/110 mm Hg, with acceptable agents including oral nifedipine or intravenous labetalol or hydralazine 1.
• Treatment should aim for a target diastolic BP of 85 mm Hg (and systolic BP of 110–140 mm Hg) to reduce the likelihood of developing severe maternal hypertension and other complications, such as low platelets and elevated liver enzymes with symptoms 1.
• Antihypertensive drugs should be reduced or ceased if diastolic BP falls < 80 mm Hg, with acceptable agents including oral methyldopa, labetalol, oxprenolol, nifedipine, and second or third line agents hydralazine and prazosin 1.
• Magnesium sulfate should be administered for seizure prophylaxis in women with preeclampsia who have proteinuria and severe hypertension, or hypertension with neurological signs or symptoms 1.
• Fetal monitoring in preeclampsia should include an initial assessment to confirm fetal well-being, with serial fetal surveillance with ultrasound as needed, and maternal monitoring should include BP monitoring, repeated assessments for proteinuria, clinical assessment, and twice weekly blood tests for hemoglobin, platelet count, and tests of liver and renal function 1.
• Delivery should be considered if the woman has reached 37 weeks’ gestation or if she develops any of the following: repeated episodes of severe hypertension, progressive thrombocytopenia, progressively abnormal renal or liver enzyme tests, pulmonary edema, abnormal neurological features, or nonreassuring fetal status 1.

From the FDA Drug Label

Rapid Decreases of Blood Pressure Caution must be observed when reducing severely elevated blood pressure A number of adverse reactions, including cerebral infarction, optic nerve infarction, angina, and ischemic changes in the electrocardiogram, have been reported with other agents when severely elevated blood pressure was reduced over time courses of several hours to as long as 1 or 2 days The desired blood pressure lowering should therefore be achieved over as long a period of time as is compatible with the patient's status.

The management of preeclampsia involves careful control of blood pressure. For blood pressure control, labetalol (IV) can be used, but caution must be observed when reducing severely elevated blood pressure. The goal is to achieve the desired blood pressure lowering over a period of time that is compatible with the patient's status, to avoid adverse reactions.

• Key considerations for blood pressure control in preeclampsia include:
  • Avoiding rapid decreases in blood pressure
  • Monitoring for potential adverse reactions, such as cerebral infarction, optic nerve infarction, angina, and ischemic changes in the electrocardiogram
  • Adjusting the dose and administration of labetalol (IV) as needed to achieve the desired blood pressure lowering while minimizing the risk of adverse reactions 2

From the Research

Blood Pressure Control for Preeclampsia

• The management of severe preeclampsia includes the use of antihypertensive agents to control blood pressure, with the goal of preventing complications such as eclampsia, HELLP syndrome, and acute kidney injury 3.
• Several studies have compared the efficacy of different antihypertensive agents, including nifedipine, labetalol, and hydralazine, in reducing blood pressure in patients with severe preeclampsia.

Comparison of Antihypertensive Agents

• A study published in 2016 found that oral nifedipine and intravenous labetalol were effective in reducing blood pressure in patients with severe preeclampsia, with no significant difference in the time taken to achieve target blood pressure 4.
• Another study published in 2022 found that nifedipine was the most effective drug in reducing blood pressure when a single dose was administered, but required more doses to further reduce blood pressure, while hydralazine was the most effective when the drug administration was maximized up to three doses within 60 minutes with 20 minutes interval 5.
• A study published in 2023 found that intravenous labetalol was more effective than intravenous hydralazine in reducing systolic and diastolic blood pressure in patients with severe preeclampsia, and required fewer doses 6.
• A systematic review and network meta-analysis published in 2019 found that nifedipine was superior to hydralazine in successfully treating severe hypertension in pregnancy, but not labetalol, and was not associated with an increased risk of caesarean delivery or maternal side effects 7.

Treatment Options

• The choice of antihypertensive agent for the treatment of severe preeclampsia depends on various factors, including the severity of the disease, the presence of comorbidities, and the patient's response to treatment.
• Oral anti-hypertensive agents, including labetalol, nifedipine, and methyldopa, are often tried first, and if they fail to adequately control blood pressure, intravenous anti-hypertensives such as labetalol, hydralazine, and glyceryl trinitrate may be considered 3.