Definition This condition is characterised by severe nausea and vomiting during pregnancy. It can result in serious dehydration, or low fluid levels in the body, and the disturbance of electrolyte, or mineral, levels in the blood.
What is going on in the body? At least three-fourths of all pregnant women have some nausea and vomiting. In many cases, it is mild and temporary. It is so severe for some women, however, that it interferes with getting the fluids and nutrients they need. If dehydration leads to serious problems with fluid and electrolyte balance in the blood, the woman may need to enter the hospital. Intravenous fluids, given through a vein in the arm or hand, may also be required.
The cause of pregnancy-related nausea and vomiting remains unclear. Movement of the bowels is slower during pregnancy. The time it takes for the stomach to empty is also longer. This is usually reflected by symptoms of constipation and heartburn. The hormone progesterone may cause these problems. In addition, high levels of oestrogen are known to cause nausea.
Symptoms typically begin at 5 to 6 weeks of pregnancy. Symptoms may last into the early second trimester. Often, nausea is more common when getting up in the morning, thus the name "morning sickness." But, it may be present at any time of the day. The nausea may also be triggered by the smell of certain foods or cigarettes. Another factor is that pregnant women may produce an excess of saliva. This condition, called ptyalism, may also bring on nausea and vomiting. Hyperemesis gravidarum is the most severe form of the condition.
What are the signs and symptoms of the condition? Symptoms of hyperemesis gravidarum include:
severe nausea
persistent and excessive daily vomiting
inability to keep down any fluids
weight loss
lightheadedness
fainting, or syncope
What are the causes and risks of the condition? Extreme nausea and vomiting in pregnancy may indicate other potentially serious disorders. These include:
hyperthyroidism
hydatidiform mole, which is an abnormal tumourous growth of the placenta
cholecystitis, which is an inflammation of the gallbladder
ulcers
What can be done to prevent the condition? There is no known prevention for this condition.
How is the condition diagnosed? Diagnosis is based on a history of the woman's symptoms and a physical examination. Laboratory tests are also done to look for indications of dehydration and electrolyte imbalances. Signs may include:
low blood pressure
rapid pulse rate
ketones, or the breakdown of fat in the urine
serum acetone, a specific type of ketone
increased blood count, or haematocrit
low potassium level in blood
low urine output
highly concentrated urine
Tests that may help to rule out other disorders include:
ultrasound to look for twins or a tumourous growth of the placenta
What are the long-term effects of the condition? Hyperemesis gravidarum usually goes away by the second half of pregnancy. It generally does not present serious long-term problems for the mother or infant.
What are the treatments for the condition? The primary treatment for the problem is dietary changes. These include:
eating frequent small meals rather than three large ones
avoiding unappealing foods
not forcing milk products into the diet which may be difficult to digest for some women
discontinuing antenatal vitamins and iron until nausea and vomiting subside
drinking plenty of fluids to stay hydrated
In severe cases, a woman may need to enter the hospital for IV fluids and electrolyte supplementation. Medications can also be used to calm the nausea. These include drugs with antihistamine or phenothiazine characteristics. Examples are:
promethazine
prochlorperazine
Doctors may be hesitant to suggest medications for pregnant women. However, these drugs have been successfully used to treat hyperemesis gravidarum without long-term problems for the mother or infant. Used correctly, medication can safely help a pregnant woman get the fluids and nutrients she needs.
What are the side effects of the treatments? The side effects depend upon which drugs are used to control nausea.
What happens after treatment for the condition? Hyperemesis usually clears up by the second trimester. If a woman is not gaining enough weight she may need to be given IV fluids and nutrients. Women who experience hyperemesis often do so in later pregnancies as well.
How is the condition monitored?
Author: Eva Martin, MD Reviewer: eknowhow Medical Review Panel Editor: Dr John Hearne Last Updated: 12/06/2005 Contributors Potential conflict of interest information for reviewers available on request
