SNOWMASS, COLO. — Don't hesitate to continue β-blocker therapy throughout pregnancy when the situation calls for it, Dr. Carole A. Warnes urged at a conference sponsored by the Society for Cardiovascular Angiography and Interventions.
“In practice I have been using β-blockers in pregnancy for 30 years. I've never had a significant problem with a baby after the mother has had a β-blocker,” said Dr. Warnes, professor of medicine at the Mayo Clinic, Rochester, Minn.
“Do we worry about the growth of the fetus? Yes, and it needs to be monitored. At the time of delivery the baby may be bradycardic or may have hypo- glycemia, but we can deal with that very easily. So for the woman who needs a β-blocker—for example, a patient with hypertrophic cardiomyopathy, or perhaps hypertension with a dilated aorta—we can use them and use them safely. And if it's better for the mother to continue, then we do so,” she asserted at the conference, which was cosponsored by the American College of Cardiology.
There are four key principles to keep in mind when prescribing cardiovascular drugs in pregnancy: Stick to those with a long safety record, use the lowest effective dose and for the shortest duration, avoid multidrug regimens, and steer clear of agents labeled category D or X by the Food and Drug Administration, Dr. Warnes advised.
In addition to many of the β-blockers, other cardiovascular drugs that Dr. Warnes listed as being relatively safe during pregnancy include calcium channel blockers, digoxin, procainamide, methyldopa, hydralazine, and furosemide.
Agents that are not safe during pregnancy include statins, ACE inhibitors, angiotensin receptor blockers, phenytoin, and folic acid antagonists, including some antibiotics, she noted.