Hyperemesis gravidarum is a severe type of morning sickness. It can last much longer than typical pregnancy-related nausea and vomiting, potentially persisting throughout the pregnancy.
Women with hyperemesis gravidarum may vomit so frequently that they become dehydrated or lose weight.
While between one-quarter and one-half of all pregnant women experience nausea and vomiting, just 0.3–3% have hyperemesis gravidarum.
Women with hyperemesis gravidarum feel intensely sick during pregnancy. For some, symptoms appear rapidly over a few weeks. For others, vomiting and nausea get steadily worse.
Doctors do not fully understand why some women develop hyperemesis gravidarum, but there is some evidence to suggest that the cause may be genetic.
Some studies indicate that genetic changes in certain hormone receptors — namely, PGR, IGFBP7, and GFRAL — may increase the risk. Variants in two genes that affect appetite and placenta development, called GDF15 and IGFBP7, may also elevate the risk.
Doctors once believed that vitamin B deficiency, reflux, hyperthyroidism, Helicobacter pylori infection, or psychological problems could cause hyperemesis gravidarum. However, current research does not support these factors as causes.
No lab test can confirm whether a woman has hyperemesis gravidarum. Instead, doctors rely on symptoms.
Different providers apply different criteria when diagnosing hyperemesis gravidarum, which makes it difficult to get an accurate, early diagnosis. Women worried about their symptoms should seek a second opinion if they feel that a doctor is dismissing their concerns.
Some doctors distinguish hyperemesis gravidarum from typical pregnancy nausea and vomiting by looking for specific symptoms, such as:
- weight loss
- chemicals called ketones in the urine, although some research does not support this as a diagnostic factor
Women may have a higher risk of hyperemesis gravidarum if they:
- have migraines outside of pregnancy
- experience nausea or vomiting when they are not pregnant
- are having a multiple pregnancy
- take medications containing estrogen
Women who smoke and those who use multivitamins before they reach the sixth week of pregnancy are less likely to get hyperemesis gravidarum, though doctors do not know why.
Treatment for hyperemesis gravidarum focuses on three goals:
- reducing or eliminating nausea and vomiting
- preventing dehydration, weight loss, and nutritional deficiencies that could endanger the pregnant woman or fetus
- supporting families to manage the stress of the condition
The right treatment depends on the severity of vomiting. Women with severe hyperemesis gravidarum need treatment in the hospital, where they can receive intravenous fluids and nutrition.
Anyone whose nausea is severe enough to cause dehydration or electrolyte imbalances should not eat anything by mouth until the vomiting stops. In the most severe cases, a doctor may recommend inserting a tube through the nose to provide nutrition via nasogastric feeding for the duration of the pregnancy.
Other treatment options include:
- Dietary changes: Eating more carbohydrates and fewer fats and acids may help. Some women also experience improvements when they eat more frequent but smaller meals. Protein-rich foods can also ease symptoms.
- Supplements: Thiamine, vitamin B-6, and vitamin C may help. Some women find relief from combining vitamin B-6 with the sleep aid doxylamine (Unisom).
- Mental health support: Chronic vomiting can be exhausting and stressful, particularly if a woman has to stay in the hospital. Support groups and therapy can help them manage this chronic stress.
- Rest: Rest may help the body recover from vomiting while easing the stress of hyperemesis gravidarum.
- Ginger: Ginger can help relieve morning sickness and may also be effective for the intense nausea of hyperemesis gravidarum.
- Antinausea drugs: A doctor can prescribe drugs to reduce the severity of vomiting and nausea.
- Alternative medicine: Some alternative and complementary therapies may help, especially when a woman uses them along with medical treatment. Acupuncture and hypnosis both show promise.
Doctors do not understand what causes hyperemesis gravidarum, and there is little evidence that any specific strategy can prevent it.
A Norwegian study found no significant dietary differences between women who developed the condition and those who did not. However, women with hyperemesis gravidarum did eat less seafood, drink less water, and consume fewer vegetables belonging to the allium group, such as onions and leeks.
Women who experience hyperemesis gravidarum in one pregnancy are more likely to have it in another pregnancy. A 2011 study found that 37% of 100 pregnant women with a history of hyperemesis gravidarum were unwilling to become pregnant again because of concerns about recurrence.
Talking to a doctor before becoming pregnant again may help a woman identify management strategies.
With proper management, hyperemesis gravidarum is a temporary source of discomfort and stress.
However, without treatment, it can cause serious complications for both the pregnant woman and the developing fetus. These may include:
- Wernicke’s encephalopathy, a dangerous neurological condition that can cause confusion, speech and communication issues, and other complications
- electrolyte imbalances
- severe malnourishment
- blood clots because of severe dehydration
- damage to the teeth because of excessive vomiting
- damage to the placenta
- low birth weight
- preterm labor
- congenital disabilities in the fetus
Rarely, severe untreated hyperemesis gravidarum can be fatal.
Doctors once attributed hyperemesis gravidarum to psychological factors. Research now shows that it is a physical health condition that warrants treatment.
Nausea and vomiting are common in early pregnancy. When these symptoms interfere with daily functioning, however, they may be a sign of hyperemesis gravidarum.
Pregnant women should see a doctor if:
- nausea is severe, or they vomit at least once daily
- vomiting and nausea do not get better in the second trimester
- they vomit so much that they cannot gain weight or begin losing weight
- it is impossible to keep down any food
- they feel weak, shaky, confused, or dehydrated
If a woman feels as though her doctor has dismissed her condition, she should seek treatment from another clinician because of the potentially serious complications of this disorder.
It is essential to go to the emergency room for signs of confusion, intense fatigue, or loss of consciousness.
Hyperemesis gravidarum is much more severe than the vomiting and nausea that many pregnant women experience.
Although there is no cure for this condition, treatment can reduce the severity of the symptoms and prevent serious complications.
It may be necessary to try several remedies until something works. A doctor can offer an array of treatment options to suit the woman’s lifestyle and health needs.