OTC Medication Warning for Pregnant Women with Severe Morning Sickness

Pregnant Women with Severe Morning Sickness

Severe morning sickness - medically know as hyperemesis gravidarum (HG) - is a malady that affects up to 2 percent of pregnant women. One of the effects of the condition is lack of sleep leading many pregnant women to take sleeping aids such as antihistamines for relief. However, in spite of the generally recognized safety of taking an over-the-counter (OTC) antihistamine medication like Benadryl, recent research indicates that doing so during a pregnancy may actually be harmful to the unborn infant.

According to a news release issued by UCLA Health Sciences, the recent study published in the European Journal of Obstetrics & Gynecology and Reproductive Biology is the result of research conducted by scientist Marlena Fejzo, an assistant professor of research in obstetrics and gynecology at UCLA who at one time nearly died from severe morning sickness during a pregnancy and later was the first to link antihistamine use to adverse pregnancy outcomes.

“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,” said Fejzo. “Women and their healthcare providers should be aware of the risk for adverse outcomes when deciding which medications to take to treat their HG symptoms.”

In the study, Dr. Fezjo and colleagues conducted a controlled study in which the outcomes of first pregnancies were compared between 254 women with severe morning sickness and 308 women who served as controls with either normal or no morning sickness. Furthermore, a comparison was made between women with severe morning sickness who either had a healthy pregnancy come to term without adverse effects and women who had a pregnancy resulting in adverse effects such as a premature birth and/or low birth weight. The comparative analysis involved looking at numerous medications and treatments commonly used by the women during their pregnancy.

What the study revealed was that:


• Women with severe morning sickness have greater than a 4-fold increased risk of poor outcome including preterm birth and lower birth weight.

• Poor outcomes were associated with early start of symptoms of severe morning sickness, gestational hypertension, and treatment with antihistamines.

• Among the women with severe morning sickness (from nearly 50% of those with an adverse outcome) taking an antihistamine was found to be less than 20% effective.

“Some doctors will suggest that their HG patients take Unisom to help them sleep through their nausea,” states Dr. Fejzo. “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.”

Image Source: Courtesy of PhotoBucket

Reference: “Antihistamines and other prognostic factors for adverse outcome in hyperemesis gravidarum” European Journal of Obstetrics & Gynecology and Reproductive Biology, 2013; DOI: 10.1016/j.ejogrb.2013.04.017; Marlena S. Fejzo, Aromalyn Magtira, Frederic Paik Schoenberg, Kimber MacGibbon, Patrick Mullin, Roberto Romero, Khalil Tabsh.