Morning sickness: what is hyperemesis gravidarum?

Up to 85 percent of women experience occasional nausea and vomiting during pregnancy (usually referred to as “morning sickness”), but hyperemesis gravidarum is an extreme version of this more typical pregnancy symptom. Affecting up to 2 percent of pregnancies, hyperemesis has no standard definition but is generally regarded as extreme nausea and vomiting when other causes (such as thyroid disorder or infections) have been ruled out.

Hyperemesis is the most common reason women are admitted to the hospital in their first trimester — even Kate Middleton was affected! Hospitalization for evaluation and treatment is needed when a woman is clinically dehydrated, is unable to control her vomiting, and is unable to take in anything by mouth.

The causes of hyperemesis are likely varied, but high levels of the pregnancy hormone hcg is likely partly to blame. Elevated levels of estrogen can also have the same effect. Other risk factors for hyperemesis include a history of having it in a prior pregnancy or a family history of hyperemesis, carrying twins or triplets, or carrying a female fetus.

There are various nonpharmacologic treatments for hyperemesis. Some studies have actually shown that taking a multivitamin at the time of conception decreases the need for medical attention for vomiting — so be sure to take your vitamins when you are trying to conceive! Other treatments include avoiding foods or smells that trigger nausea, resting, and eating small, frequent meals. Ginger has also been shown to help. Bracelets providing pressure to points on the wrist have been studied, but most studies have been of poor quality.

As for medications, there are effective options available. Pyridoxine (vitamin B6) used with or without doxylamine (the agent found in Unisom) has been shown to effectively treat nausea and vomiting in many pregnant women. Other anti-nausea medications are also available, but they require a prescription from your doctor. If very severe, your doctor may also prescribe you steroids or use them intravenously if you are admitted to the hospital.

It is normal to worry if hyperemesis is affecting your developing baby. The good news is that most pregnancies progress just fine. Some studies have shown a higher incidence of low birth weight infants born to moms with hyperemesis, but not all. There are no studies showing adverse developmental outcomes in babies born to moms who had hyperemesis gravidarum.