When we learned that Britain’s Kate Middleton was hospitalized due to “acute morning sickness,” many people had questions about the condition – how it differs from ordinary morning sickness experienced by pregnant women, and what it might mean for Kate and the baby she is expecting with her husband, Prince William. For answers, we turned to Christian Pettker, M.D., of the Department of Obstetrics and Gynecology at Yale School of Medicine.

Ask Yale Medicine: Please describe the condition Hyperemesis Gravidarum. What is it, and why would a pregnant woman wind up in the hospital?

Dr. Pettker: Nausea and vomiting are common early symptoms of pregnancy. The most serious cases fall under the diagnosis of hyperemesis gravidarum (HG), which typically presents as nausea and vomiting leading to dehydration, weight loss, decreased nutrition, and abnormal salt (electrolyte) balance. It is very rare that it becomes serious enough to need hospitalization, but this sometimes is necessary if the woman needs an IV for hydration, medications, or nutrition.

AYM: What might cause it?

Dr. Pettker: We don’t know the exact cause of HG, but there is probably some influence of hormones related to pregnancy (estrogen and human chorionic gonadotropin). These are normal hormones of pregnancy which can be elevated in the first trimester. We do know that certain pregnancy conditions, such as twins and triplets, make a woman more at risk for severe nausea and vomiting.

AYM: What percentage of pregnant women suffer from it?

Dr. Pettker: About 75% of pregnant women will experience some form of nausea or vomiting during pregnancy. HG occurs in about 1-2% of pregnancies.

AYM: How long into the pregnancy does it last?

Dr. Pettker: Nausea and vomiting typically is limited to the first trimester (up to 14 weeks).  Sometimes it can last through 20 weeks, in severe cases.

AYM: What is the treatment?

Dr. Pettker: The first steps are to change some behaviors.  Eating more frequent meals of smaller portions seems to work. We also often recommend bland food with a high-protein content. First-line treatments proven in clinical trials include vitamin B6 and ginger (teas, capsules, or candies).  Devices that provide pressure at the P6 pressure point on the inside of the wrist may help. There are also many different prescription medications available. Usually we prescribe these to be taken by mouth, but some medications can be used as suppositories for patients who are not able even to swallow pills. When these medications don’t work, we use intravenous medications, often supplementing this with intravenous hydration.

AYM: Can it be harmful to the mother or fetus?

Dr. Pettker: Rarely do the mothers suffer enough to become seriously ill.  Supplemental feeding, through a feeding tube or through a bloodstream catheter, is hardly ever necessary.  There is conflicting evidence if there is any significant effect on the fetus; there may be a higher incidence of low birth weight in mothers with severe HG.  What seems to be clear in the medical literature is that women with HG have a lower risk for miscarriage, a reassuring point that we make sure to emphasize to patients.

AYM: Is there any way to prevent it?

Dr. Pettker: Taking a multivitamin before and at the beginning of the pregnancy appears to be a good prevention for women who have had a history of nausea and vomiting or hyperemesis.

For more information on Dr. Christian Pettker: http://medicine.yale.edu/obgyn/people/christian_pettker.profile

Photo courtesy Featureflash/Shutterstock.com

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