Coreg CR® (
carvedilol CR) is a prescription
beta blocker medication. Based on the results of animal studies, this medication may not be safe for use in pregnancy (although the full risks are not currently known).
The U.S. Food and Drug Administration (FDA) uses a pregnancy category system to classify the possible risks to a fetus when a specific medicine is taken during pregnancy. Pregnancy Category C is given to medicines that have not been studied in pregnant humans but do appear to cause harm to the fetus in animal studies. Also, medicines that have not been studied in any pregnant women or animals are automatically given a pregnancy Category C rating.
Studies that were conducted in pregnant rats and rabbits showed an increased risk for miscarriages and decrease in body weight with doses of
carvedilol (the active ingredient in
Coreg CR) up to 50 times the normal human dose. No birth defects were reported.
Little human research has been conducted on the effects that Coreg CR or any other beta blockers may have on the fetus. With other beta blockers, there have been individual reports of slowed growth (before birth), small placentas, and birth defects in women who took these drugs during pregnancy. There have also been reports of a very low heart rate, low blood sugars, and/or decreased breathing in some fetuses when beta blockers were used during childbirth.
It is important to note that animals do not always respond to medicines the same way that humans do. Therefore, a pregnancy Category C medicine may be given to a pregnant woman if a healthcare provider believes that the benefits to the pregnant woman outweigh any possible risks to the unborn child.