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David Geffen School of Medicine

Antihistamines May Pose Risk to Women with Severe Morning Sickness

Antihistamines May Pose Risk to Women with Severe Morning SicknessWomen with severe morning sickness who take antihistamines to help them sleep are significantly more likely to experience premature births or have low-birth-weight babies, a UCLA study has found. Women with this severe form of morning sickness who are considering taking such medications should know the risks, says Marlena Fejzo, PhD, assistant professor of research in obstetrics and gynecology.

The cause of severe morning sickness, called hyperemesis gravidarum (HG), is unknown and the symptoms are intense and can last for several months or throughout the pregnancy. The continuous nausea and vomiting can be so violent that women report suffering from detached retinas, blown eardrums, cracked ribs and torn esophagi.

“It was surprising to find the link between antihistamines and adverse outcomes as these are over-the-counter medications that are used commonly by women with HG during pregnancy,” says Dr. Fejzo.

The six-year study compared pregnancy outcomes in two groups of women. The first was composed of 254 women with HG who were sick enough to require treatment for dehydration with intravenous fluids. The second was made up of 308 women with normal or no morning sickness during pregnancy. The researchers found women with HG had four times the risk of adverse outcomes, confirming a link between HG and adverse outcomes that had been shown in several previous studies. The study then compared women with HG who suffered adverse outcomes to women with HG who had good outcomes. Researchers looked at whether any of more than 35 medications and treatments commonly used by women with HG were linked to bad outcomes. They found that more than 50 percent of HG patients who experienced adverse outcomes took over-the-counter medications containing antihistamines.

“Some doctors will suggest that their HG patients take antihistamine to help them sleep through their nausea,” Dr. Fejzo says. “Our findings show not only that the use of antihistamines is linked with adverse outcomes, but also that they’re not that effective. Women with HG should be aware of that, so they can make educated decisions on how to treat their HG symptoms.”

“Antihistamines and other Prognostic Factors for Adverse Outcomes in Hyperemesis Gravidarum,” European Journal of Obstetrics & Gynecology and Reproductive Biology, June 10, 2013


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