What is the indication for rapid-acting agents for the treatment of hypertensive disorders of pregnancy?

Updated: Jun 12, 2018
  • Author: Michael P Carson, MD; Chief Editor: Edward H Springel, MD, FACOG  more...
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If a pregnant woman's blood pressure is sustained greater than 160 mm Hg systolic and/or 110 mm Hg diastolic at any time, lowering the blood pressure quickly with rapid-acting agents is indicated for maternal safety. [4] Anticonvulsant therapy may be undertaken in the setting of severe preeclampsia (primary prophylaxis) or in the setting of eclamptic seizures (secondary prophylaxis). The most effective agent is IV magnesium sulfate; phenytoin is an alternative, although less effective, therapy.

Methyldopa has an established safety record, but it is a mild antihypertensive with a slow onset of action, and associated fatigue may limit patient tolerability of this medication.

Labetalol has a more rapid onset of action, may be given orally or parenterally, and is generally preferred as a first-line agent. [22] One retrospective case-control propensity-score matched study evaluated the association between late trimester exposure to beta-adrenergic blockade with labetalol, metoprolol, and atenolol. and neonatal bradycardia or hypoglycemia. There was a small association between labetalol and neonatal hypoglycemia, the absolute rate in the exposed group was 4.3% versus 1.2% in the nonexposed propensity-score matched group. Labetalol is an effective well tolerated medication that can still be considered a first line agent, and as with any maternal medication, maternal medications should be reviewed by the pediatrician to determine proper neonatal monitoring. [23]

The association between these medications and neonatal hypoglycemia is limited by higher respective prevalences of preexisting and gestational diabetes in the exposed vs. unexposed groups (13.9% vs. 3.8% and 20.6% vs. 8.3%). In spite of a sensitivity analysis, women with diabetes are more likely to have their infants screened for hypoglycemia, so a detection bias cannot be totally excluded. [23]

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