By Kathryn Doyle
NEW YORK (Reuters Health) - A woman's use of decongestant medications in the first trimester of pregnancy may raise her child's risk of certain rare birth defects, according to a small study.
Some types of over-the-counter decongestants, including the popular phenylephrine and pseudoephedrine, were individually linked to rare, specific birth defects of the digestive tract, ear and heart.
"Major birth defects of any kind affect about two to three percent of liveborn infants, so they are rare," study author Dr. Allen Mitchell said. "The associations we identified involved defects that generally affect less than 1 per 1,000 infants. Some of them may require surgery, but not all are life-threatening."
Decongestants are some of the most commonly used drugs, however, so fully understanding the consequences of taking them during pregnancy is important, said Mitchell, director of the Slone Epidemiology Center at Boston University.
His team worked with a large collection of data on babies born with birth defects between 1993 and 2010. Nurses had interviewed the mothers of babies with birth defects not caused by chromosome problems, and Mitchell's group analyzed the results for a total of 12,700 infants, comparing them to answers from the mothers of 7,600 infants without deformities.
Mothers were asked about medications they took while pregnant and in the two months before becoming pregnant.
First-trimester use of phenylephrine, which is found in Sudafed among other products, was tied to an eight-fold higher risk of a heart defect called endocardial cushion defect. And phenylpropanolamine (Acutrim) was also linked to an eight-fold risk of defects of the ear and a three-fold increase in stomach defects. All were associations that had been suggested by earlier studies.
But for the first time, the authors found links between first-trimester use of pseudoephedrine (also in Sudafed) and a 3-fold higher risk of so-called limb reduction defects. Use of imidazolines (found in nasal decongestant sprays and eye drops) was tied to an approximate doubling of risk for an abnormal connection between the trachea and esophagus.
"The risks we identified should be kept in perspective," Mitchell cautioned. "The risk of an endocardial cushion defect among babies whose mothers did not take decongestants is about 3 per 10,000 live births."
Even the eight-fold increase in risk indicated by the study results, while it sounds large, would translate to a 2.7 in 1,000 chance the baby would have the defect, he said. Assuming the findings are correct, he added, the researchers could not speculate about why these drugs might be linked to this handful of defects.
They found no link between the medications and several other deformities that had been suggested by previous studies, such as clubfoot or defects of the eye or face, according to the report published in the American Journal of Epidemiology.
"This should offer some reassurance to women who have taken these medications in pregnancy," Mitchell said.
"Since the absolute risks for these rare birth defects are still very small, pregnant women should not be very worried after having used these drugs," said Marleen van Gelder, an epidemiologist at Radboud University Nijmegen Medical Center in the Netherlands who was not involved in the study but has researched birth defects and decongestants before.
"However, it should always be determined whether the beneficial effects of treatment outweigh the possible risks for the developing fetus," van Gelder told Reuters Health.
Mitchell believes there's enough evidence indicating a possible connection to birth defects that doctors should not be recommending that pregnant women take decongestants, but should evaluate each woman's need for the drugs on a case-by-case basis.
"The fact that medications such as decongestants are typically and widely available for use without a prescription and do not require consultation with a healthcare provider should not be assumed to mean they are safe with respect to the fetus, since there are still relatively few studies that examine the risks and relative safety of these ‘over-the-counter' medications, which are more widely used in pregnancy than prescription medications," Mitchell said.
[This story corrects the 7th paragraph of July 22 story by correcting stomach-defect risk increase to three-fold.]
SOURCE: http://bit.ly/17mAbMT American Journal of Epidemiology, online July 3, 2013.