Dr. Frank R. Witter of The Johns Hopkins University School of Medicine and Johns Hopkins University Bloomberg School of Public Health and colleagues said beta 2 adrenergic agonist drugs as a class are widely used in obstetrics to inhibit or slow down labor, and bronchodilators use a similar drug to decrease airway resistance and thereby facilitate airflow.
These drugs may act as functional and behavioral teratogens -- an agent which can cause a birth defect -- when given continuously in the mid- to late-second or early third trimesters, Witter said.
"Given the risk of long-term neurophysiologic and behavioral impairment, the use of beta 2 adrenergic agonists should be limited to proven indications when alternate drugs are ineffective or unavailable and the risks of the untreated disease to the mother and fetus are greater than the risk of the beta 2 adrenergic agonist," Witter said in a statement. "Treatment duration should be as short as clinically feasible."
The researchers did not identify the drugs used in the study, however, short-acting beta2 agonists include: salbutamol, or Albuterol, Ventolin; levosalbutamol; terbutaline, pirbuterol or Maxair; procaterol; metaproterenol or Alupent; fenoterol and bitolterol mesylate.
The findings are scheduled to be published in the December issue of the American Journal of Obstetrics & Gynecology.