Some types of over-the-counter decongestants, including the popular phenylephrine and pseudoephedrine have been linked to rare, specific birth defects of the digestive tract, ear and heart.
"Major birth defects of any kind affect about two to three per cent of live born infants, so they are rare," study author Dr. Allen Mitchell told Reuters. "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."
However, decongestants are some of the most commonly used drugs so it’s important to understand the consequences of taking them during pregnancy, said Mitchell, director of the Slone Epidemiology Center at Boston University.
His team worked with a large collection of date 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 analysed the results for over 12,000 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.
Reuters reports that first-trimester use of phenylephrine, which is found in over the counter remedies such as Sudafed among others was linked to an eight-fold higher risk of a heart defect called endocardial cushion defect.
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The report goes on to reveal that phenylpropanolamine 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.
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 oesophagus.
"The risks we identified should be kept in perspective," Mitchell warned. "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, in real terms, is 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.
"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 foetus," 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 foetus, 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.
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