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Hyperemesis gravidarum (from Greek hyper and emesis and Latin gravida; meaning "excessive vomiting of pregnant women") is a severe form of morning sickness, with unrelenting, excessive pregnancy-related nausea and/or vomiting that prevents adequate intake of food and fluids. Hyperemesis is considered a rare complication of pregnancy but, because nausea and vomiting during pregnancy exist on a continuum, there is no clear boundary between common morning sickness and hyperemesis. Estimates of the percentage of pregnant women afflicted range from 0.3% to 2%.
Additional recommended knowledge
When HG is severe and/or inadequately treated, it may result in:
Some women with HG lose as much as 20% of their body weight. Many sufferers of HG are extremely sensitive to odors in their environment; certain smells may exacerbate symptoms. This is known as hyperolfaction. Ptyalism, or hypersalivation, is another symptom experienced by some, but not all, women suffering from HG.
As compared to morning sickness, HG tends to begin somewhat earlier in the pregnancy and last significantly longer. While most women will experience near-complete relief of morning sickness symptoms near the beginning of their second trimester, some sufferers of HG will experience severe symptoms until delivery. A chart comparing morning sickness to HG can be found here.
For the pregnant woman
If inadequately treated, HG can cause renal failure, central pontine myelinolysis, coagulopathy, atrophy, Mallory-Weiss syndrome, hypoglycemia, jaundice, malnutrition, Wernicke's encephalopathy, pneumomediastinum, rhabdomyolysis, deconditioning, splenic avulsion and vasospasms of cerebral arteries. Depression is a common secondary complication of HG.
Charlotte Brontë is believed to have died from HG.
The serious, and sometimes fatal complications of HG are almost always avoided with aggressive treatment.
For the fetus
No long-term follow-up studies have been conducted on children of hyperemetic women. Children born to hyperemetic women appear to have no greater risk of complications or birth defects than the general population. However, recent research in fetal programming indicates that prolonged stress, dehydration and malnutrition during pregnancy can put the fetus at risk for chronic disease, such as diabetes or heart disease, later in life, or nuerobehaviorial issues from birth. This underscores the importance of aggressive treatment of the condition.
Because of the potential for severe dehydration and other complications, HG is generally treated as a medical emergency. Treatment of HG may include antiemetic medications and intravenous rehydration. If medication and IV hydration are insufficient nutritional support may be required.
Management of HG can be complicated because not all women respond to treatment. Coping strategies for uncomplicated morning sickness, which may include eating a bland diet and eating before rising in the morning, may be of some assistance but are unlikely to resolve the disorder on their own. There is evidence that ginger may be effective in treating pregnancy-related nausea, however this is generally ineffective in cases of HG.
IV hydration often includes supplementation of electrolytes as persistent vomiting frequently leads to a deficiency. Likewise supplementation for lost thiamine (Vitamin B1) must be considered to reduce the risk of Wernicke's encephalopathy. A and B vitamins are depleted within two weeks, so extended malnutrition indicates a need for evaluation and supplementation. Additionally, mineral levels should be monitored and supplemented, of particular concern are sodium and potassium.
After IV rehydration is completed, patients generally progress to frequent small liquid or bland meals. After rehydration, treatment focuses on managing symptoms to allow normal intake of food.
While no medication is considered completely risk-free for use during pregnancy, there are several which are commonly used to treat HG and are believed to be safe.
The standard treatment in most of the world is Benedictin (also sold under the trademark name Diclectin), a combination of doxylamine succinate and vitamin B6. However, due to a series of birth-defect lawsuits in the United States against its maker, Merrill Dow, Benedictin is not currently on the market in the U.S. (None of the lawsuits were successful, and numerous independent studies and the Food and Drug Administration (FDA) have concluded that Benedictin does not cause birth defects.) Its component ingredients are available over-the-counter (doxylamine succinate is the active ingredient in many sleep medications), and some doctors will recommend this treatment to their patients.
Antiemetic drugs, especially ondansetron (Zofran), are effective in many women. The major drawback of ondansetron is its extremely high cost. In severe cases of HG, the Zofran pump may be more effective than tablets. Metoclopramide is sometimes used in conjunction with antiemetic drugs; however, it has a somewhat higher incidence of side effects. Other medications less commonly used to treat HG include Marinol, corticosteroids and antihistamines.
Practice in United Kingdom
The practice in the United Kingdom, following the thalidomide tragedy, is to generally use older drugs for which there has been a greater experience of use in pregnancy. Hence the first choice drug is promethazine with second choice being either metoclopramide or prochlorperazine; with the administration of thiamine strongly recommended.
Women who do not respond to IV rehydration and medication may require nutritional support. Patients might receive parenteral nutrition (intravenous feeding via a PICC line) or enteral nutrition (via a nasogastric tube or a nasojejunum tube).
Complementary and alternative medicine
Some women with HG find relief with complementary or alternative medicine, including chiropractic, homeopathy, acupuncture and energy psychology.
There is anecdotal evidence for the benefits of medical marijuana, which is more widely used to treat nausea and increase appetite during chemotherapy, but has been used for the same purpose in treating HG.      The effects of cannabis on the fetus are not well understood, though no studies have yet established significant adverse effects.
The cause of HG is unknown. The leading theories speculate that it is an adverse reaction to the hormonal changes of pregnancy. In particular Hyperemesis may be due to raised levels of beta HCG (Human Chorionic Gonadotrophin) as it is more common in multiple pregnancies and in gestational trophoblastic disease.
Additional theories point to high levels of estrogen and progesterone, which may also be to blame for hypersalivation; decreased gastric motility (slowed emptying of the stomach and intestines); immune response to fragments of chorionic villi that enter the maternal bloodstream; or immune response to the "foreign" fetus.
Historically, HG has been blamed upon a psychological condition of the pregnant women. Medical professionals believed it was a reaction to an unwanted pregnancy or some other emotional or psychological problem. This theory has been disproved, but unfortunately some medical professionals espouse this view and fail to give patients the care they need.
Understanding its impact
According to the Hyperemesis Education and Research Foundation (HER), conservative estimates indicate that HG can cost a minimum of $200 million annually in inhouse hospitalizations to treat the condition. Note that this figure does not include emergency room visits, and other types of assistance, so the figure is in actuality quite higher. Beyond the immediate financial impact, many families dissolve due to the stress of HG and women can suffer long term health consequences. Many women also lose their employment due to HG and decide to limit their family size rather than experience another HG pregnancy.
Supporting women in HG pregnancy
It is important that women get early and aggressive care during pregnancy. This can help limit the complications of HG. Also, due to the fact that depression can be a secondary condition of HG, emotional support, and sometimes even counseling, can be of benefit. It is important, however, that women not be stigmatized by the suggestion that the disease is being caused by psychological issues.
Categories: Obstetrics | Medical emergencies
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Hyperemesis_gravidarum". A list of authors is available in Wikipedia.|