Labetalol has less effect on children when taken during pregnancy. Labetalol is an alpha, beta adrenergic receptor blocker that lowers blood pressure but does not affect blood flow to the kidneys or placenta of pregnant women, and counteracts platelet clumping and promotes fetal lung maturation. The drug has a rapid onset of action, few side effects, and does not cause hypotension or reflex tachycardia. It is also recommended by the U.S. Food and Drug Administration as the preferred antihypertensive drug for pregnant women, and can be used safely by pregnant women with hypertension. If labetalol alone is not effective in lowering blood pressure, it can be used in combination with other types of antihypertensive drugs, such as nifedipine and amlodipine, which are calcium antagonists, diuretics such as dihydroketuria, and the vasodilatory drugs methyldopa and hydrazidiazine.