Morning sickness is a term used to describe the nausea or vomiting many women experience during pregnancy. Other signs and symptoms including weight loss, lightheadedness and fainting may accompany morning sickness. Researchers have been unable to identify the exact cause of morning sickness, but many experts believe the condition may be caused by changes in hormone levels.
Although its name suggests that it only occurs in the morning, morning sickness can occur at any time of day. There are a number of factors that can trigger the nausea or vomiting associated with the condition. It is most common during the first trimester (first three months of pregnancy) and usually disappears by the fourth month of pregnancy. For some women, however, it may continue for the entire pregnancy. Other women never experience any morning sickness during their pregnancy.
Although the nausea and vomiting associated with the condition may be unpleasant for most expectant mothers, it usually does not result in harm for the woman or her fetus. Hyperemesis gravidarum (a disorder characterized by frequent and severe vomiting), however, can lead to dehydration and may require hospitalization.
When nausea and vomiting are severe, an obstetrician-gynecologist (ObGyn) may perform a physical examination and order blood tests (e.g., complete blood count, chem-20) and urine tests. These tests can help detect dehydration and determine if the symptoms are related to a condition other than morning sickness.
According to the National Institutes of Health (NIH), most pregnant women experience some degree of nausea and about one-third have vomiting. Mild to moderate morning sickness may be successfully treated with changes in behavior and nutrition. For example, a woman may benefit from eating five or six small meals a day rather than three large meals. Avoidance of certain foods also may reduce morning sickness in women. Although rare in most pregnant women, severe nausea and vomiting may require treatment, including medication or intravenous fluid administration.
About morning sickness
Nausea or vomiting during pregnancy is known as morning sickness. Although it is most common in the morning, it can occur at any time of day. It often occurs on an empty stomach or at night when women lay down.
Morning sickness is very common during the first three months of pregnancy (the first trimester), typically peaking between the 2nd and 12th week. It usually disappears as the pregnancy progresses, and is normally gone by the fourth month. However, some women may experience nausea or vomiting through their entire pregnancy, and others will not experience it at all.
Although morning sickness does not occur in all pregnancies, the National Institutes of Health (NIH) estimate that most women develop some level of nausea and approximately one-third experience vomiting. Experts have not determined why some women experience morning sickness, while others do not. In addition, the level of morning sickness in each pregnancy is different. As a result, a woman cannot predict the level of morning sickness in future pregnancies from her experience in one pregnancy.
Some women have heard that if they do not experience morning sickness, they will be more likely to miscarry. However, there is no conclusive evidence linking morning sickness to a successful pregnancy. Many women who experience little or no morning sickness have a normal pregnancy and successful delivery of a healthy baby.
Morning sickness is unpleasant, but it usually does not cause any harm to the expectant mother or her fetus. Severe persistent vomiting, however, can cause complications. Hyperemesis gravidarum is a condition characterized by frequent and severe vomiting. It is a concern during pregnancy because it may lead to dehydration (a depletion of body fluids). It may also interfere with the weight gain needed to supply adequate nutrition to the mother and fetus.
Women should contact their obstetrician-gynecologist (ObGyn) when:
Morning sickness does not improve with home remedies.
There is a weight loss of more than two pounds.
There is vomiting more than three times a day.
There has been an inability to keep any food or liquid down.
The vomit contains blood or looks like coffee grinds (this requires immediate medical attention).
The nausea and vomiting continues into the fourth month of pregnancy.
The urine is dark-colored.
Urination is not occurring every four to six hours.
The heart is racing or pounding.
Severe nausea and vomiting during pregnancy may indicate numerous conditions, including multiple pregnancy, and in rare cases, thyroid disorder or molar pregnancy (the growth of abnormal tissue in the uterus). To determine the cause of the condition and detect dehydration, the physician may perform a physical examination, including a pelvic examination. The patient’s blood pressure and pulse rate will be checked during the exam because an increased pulse rate and decreased blood pressure are signs of dehydration. The physician may perform additional tests to rule out other possible causes of nausea and vomiting, including abnormalities of the liver or gastrointestinal tract.
Blood tests and urine tests may be ordered to detect dehydration. Possible blood tests include a complete blood count (CBC) to detect increased levels of hematocrit (a sign of dehydration), and a chem-20 (a blood chemistry test). In addition, the woman’s urine will be analyzed for the presence of ketones and to determine the severity of dehydration. Ketones are produced when the body is forced to burn fat instead of glucose (blood sugar) for energy. They may be detectable in the urine or blood when nausea and vomiting prevent a woman from consuming enough calories.
Other symptoms related to morning sickness
In addition to nausea and vomiting, morning sickness may be accompanied by a number of other signs and symptoms, including unexplained weight loss, lightheadedness and fainting.
When nausea and vomiting are severe, dehydration may occur. Common signs and symptoms of dehydration that may be noticed by the patient may include:
Dry or sticky mouth
Little or no urine output
Dark urine
Failure to produce tears
Sunken eyes
Lethargy (when dehydration is severe)
Women experiencing any of these signs and symptoms should immediately notify their obstetrician-gynecologist (ObGyn). Their ObGyn may also order certain medical tests to detect signs and symptoms of dehydration, including:
Ketones (chemicals produced when the body uses stored fat for energy) in the urine
Increased hematocrit (level of red blood cells)
Increased pulse rate
Decreased blood pressure
Potential causes of morning sickness
The exact cause of morning sickness is unknown. Many physicians believe that hormones play a role. During pregnancy there is a sudden increase in hormones. Rising levels of human chorionic gonadotropin (HCG), a hormone secreted by the fetus, is considered a factor. Rising levels of the female hormone estrogen levels have also been implicated. Some experts believe pregnancy hormones cause nausea and vomiting by relaxing the stomach.
The hormone theory is also supported by the fact that morning sickness usually disappears by the second trimester, the time the levels of pregnancy hormones fall. In addition to hormones, lower blood sugar during early pregnancy has been considered a potential cause of morning sickness.
Many researchers believe that hormones and morning sickness played an important role during human evolution. A common theory is that morning sickness during pregnancy protects the fetus by preventing the mother from eating foods that would be harmful to the pregnancy. This idea is supported by the fact that many of the foods that commonly repulse pregnant woman contain potentially harmful substances.
In addition, some studies have indicated that women who have little or no nausea or vomiting during pregnancy seem to be more likely to miscarry than those who experience some sickness. Many physicians believe morning sickness is a positive sign because it signals that the afterbirth (the placenta and fetal membranes) is developing properly. However, this link is not certain, and many women who experience little or no morning sickness have normal pregnancies.
In some women, an increased sensitivity to odor may also contribute to morning sickness. Pregnancy may cause the development of aversions to certain foods such as coffee or meat. The dislike for these foods is often associated with their odor. Many women experience an enhanced sense of smell during their pregnancy. This can result in these women becoming more sensitive to odors, triggering nausea and vomiting. Pregnant women may also experience changes in the taste of some foods.
Treatment and prevention of morning sickness
There are many methods pregnant women can use to relieve the nausea associated with morning sickness. Common methods include avoiding certain foods and fluids such as:
Greasy or fatty foods
Highly seasoned foods
Onions and other strongly flavored vegetables
Cream or heavy dairy products
Foods that smell unpleasant
Large amounts of coffee or tea
Coffee, tea, citrus juice and milk (with meals)
Women may be able to avoid morning sickness or reduce the symptoms by following a few changes:
Eat five or six small meals a day instead of three large meals. The stomach should never feel empty because nausea is more likely to occur on an empty stomach.
Eat more carbohydrates, such as a plain baked potato, white rice or dry toast.
Eat snacks that are high in protein, such as peanut butter, nuts, pasteurized cheese, cottage cheese and yogurt.
Eat bland foods when feeling nauseous, including saltine crackers, gelatin, broth and ginger ale.
Eat saltine crackers or dry bread before going to sleep at night and upon waking in the morning. A small snack should also be eaten when getting up to go to the bathroom in the middle of the night. Many women find it helpful to keep crackers by their bed to help prevent nausea in these situations.
Drink fluids often throughout the day. Drinking fluids is important to prevent dehydration. To avoid nausea, drink liquids between meals instead of during meals. Try broth, caffeine-free soft drinks, sports drinks, fruit juice, seltzer or other types of sparkling water. If liquids upset the stomach, try eating crushed ice or popsicles. Most women become aware of which drinks are better tolerated.
Other helpful tips include:
Get plenty of rest and take breaks when periods of low energy arise.
Get up slowly in the morning. Sit on the side of the bed for a few minutes before standing up. Eat a cracker or sip a drink before getting up.
Suck on a piece of hard candy.
Wear an acupuncture wristband. Commonly worn by boat and airline passengers to prevent motion sickness, these wristbands may help alleviate morning sickness. They work by placing pressure on an accupressure point on the inside wrist. They are available at drug stores, health food stores, boating stores and travel agencies. Although they do not work for everyone, many women report relief with these bands.
Take prenatal vitamins at night. The iron in prenatal vitamins can cause nausea in some women. Taking the vitamins at night or on a full stomach may help prevent morning sickness. If the nausea persists, discuss the vitamins with a physician. The physician may choose to change the vitamins.
Increase the amount of vitamin B-6. Sources of vitamin B-6 include whole grains, nuts, seeds and legumes. A physician may also suggest vitamin B-6 supplements.
Consume ginger. The spice can be found in ginger soda, ginger tea and gingersnaps. It is also available in capsules and a crystallized form that can be sucked or chewed. Ginger has been shown to relieve nausea and other symptoms of motion sickness.
Avoid strong or unpleasant smells.
Keep rooms well-ventilated to reduce odors. Also, cool temperatures may be better for some women.
Avoid smoking and second-hand smoke.
Keep a record of what elements may have contributed to the morning sickness. By avoiding the items, such as certain foods or drinks, women may reduce the chance of sickness.
Although there are medications available to treat morning sickness, women should always discuss these options with their obstetrician-gynecologist (ObGyn) before taking them. Women should also discuss nutritional or herbal supplements, such as ginger capsules and B-6 supplements, with their physician before using them. Women who are considering alternative treatments, such as acupuncture, should discuss these options with their physician as well. It is also important only to use individuals involved in complementary and alternative medicines who are trained to work with pregnant women.
Unlike typical morning sickness, hyperemesis gravidarum (a disorder characterized by frequent and severe vomiting) may require medical treatment. When vomiting is frequent, and severe enough to pose a threat to the expectant mother or her fetus, medication may be prescribed to reduce nausea and vomiting. In severe cases, the mother may require hospitalization and intravenous (I.V.) fluid administration to balance the level of electrolytes in the blood. Treatment may also require fasting, followed by a slow introduction of food back into the diet.
Questions for your doctor on morning sickness
Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Women may wish to ask their doctor or healthcare professional the following questions about morning sickness:
How likely is it that I will develop morning sickness?
What do you recommend to reduce my symptoms?
How severe should my nausea and vomiting be before I call you?
Should I be taking vitamin B-6 supplements?
When will my morning sickness end?
What steps will be taken if my morning sickness persists?
Can I use alternative treatments, such as acupuncture or herbs?
If I don't have any morning sickness, is it a bad sign?
How do I know if I'm dehydrated?
How do I know if my vomiting is related to something other than morning sickness?
Can I take over-the-counter medicines to help my nausea?
Am I likely to experience morning sickness in future pregnancies?
