A new UCLA study is the first to associate antihistamine use in women with hyperemesis gravidarum (condition characterized by severe nausea, vomiting, weight loss, and electrolyte disturbance) to adverse pregnancy outcomes. These new findings are important due to the fact that babies born before 37 weeks are frequently hospitalized longer than full term babies and could have health problems including breathing and feeding, more apt to infection and can endure developmental problems.
According to Dr. Marlena Fejzo, PhD, Research Faculty, Departments of Obstetrics and Gynecology, and Medicine and lead author of study said that women with this condition considering taking such medications should know the risks.
Hyperemesis gravidarum is an uncommon disorder in which extreme, persistent nausea and vomiting occur during pregnancy. This condition might lead to dehydration. This is the same condition Duchess Kate Middleton experienced last December. The cause of this condition remains unknown with intense symptoms. The nausea and vomiting can become so severe that women in the study reported suffering from detached retinas, blown eardrums, cracked ribs and torn esophagi, said Dr. Fejzo.
This six year case-control study compared pregnancy outcomes between 254 women with hyperemesis gravidarum treated with intravenous fluids and 308 controls (normal or no morning sickness during pregnancy).
The results revealed women with hyperemesis gravidarum have over a 4-fold increased risk of poor outcome including preterm birth and lower birth weight.
Poor outcomes were associated with early start of symptoms and treatment with methylprednisolone, promethazine, and other antihistamines; Benadryl, Gravol, Unisom, Vistaril/Atarax and Diclectin/Bendectin, independent of effectiveness. Dr. Fejzo found that these antihistamines were taken by more than 50% of HG patients who experienced adverse outcomes.
Also, the medications were effective in less than 20% of cases.
In their conclusion the research team writes “Poor outcomes are significantly greater in women with HG and are associated with gestational hypertension, early symptoms, and antihistamine use. Given these results, there is an urgent need to address the safety and effectiveness of medications containing antihistamines in women with severe nausea of pregnancy.”
Dr. Fejzo commented “Some doctors will suggest that their HG patients take Unisom to help them sleep through their nausea.” “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.”
Currently Dr. Fejzo and her team are studying outcomes in HG pregnancies to determine if the violent nausea and vomiting have any effects on the children later in life.
In closing Dr. Fejzo remarks “We desperately need support for research into HG to determine its cause so that medications can be designed that are safe and effective.” “The greatest risk factor for HG other than a previous HG pregnancy is having a sister who had HG, which increases the risk by 17-fold. This suggests a genetic component is at work.”
Fejzo and her team are collecting saliva from women with HG and women with normal pregnancies and are studying the DNA extracted from the saliva to look for genes that may predispose women for HG. She hopes once a cause is discovered, drugs can be developed to either prevent or more effectively treat the condition.
Researchers also found that outpatient treatment with alternative medicine such as acupressure or acupuncture was associated with a positive outcome.
A small percentage (about 1 to 2%) of women develops a severe form of nausea and vomiting of pregnancy called hyperemesis gravidarum. With this condition, nausea and vomiting may be constant, and women often have weight loss, dehydration, and changes in their metabolic state.
