Morning Sickness

September 17, 2011

The existence of morning sickness early in pregnancy seems difficult to explain. Maybe it is just a mistake, an accident of nature. We all know that the first few months of fetal development are critical for the baby’s health. Why then are so many women so sick early in pregnancy, and what can be done to help them? Finally, is it possible that morning sickness is actually a good thing to have?


It would be more accurate to refer to morning sickness as “all-day” sickness because for many pregnant women it is, although it is frequently worse in the

mornings. The preferred medical term is nausea and vomiting of pregnancy (NVP). Morning sickness can range in severity from none (20% of all pregnant women do not get it at all) to persistent vomiting so severe that hospitalization and treatment with intravenous fluids are necessary. Typically, morning sickness is a near-constant feeling of nausea, intermittent vomiting, and an increased sensitivity/aversion to odors. It usually begins about weeks 5 or 6 of pregnancy and usually is fully resolved by about week 14.


Many articles link morning sickness to the pregnancy hormone human chorionic gonadotropin (HCG), which is unique to pregnancy. For example, morning sickness tends to be worse with multiple gestation (a high-hormone state) and it tends to be minimal in pregnancies that end in miscarriage (a low-hormone state). Many patients understand that the sicker they are, the “better” the pregnancy. This theory does not explain everything, however. Why does morning sickness exist at all? Is there some reason, perhaps something related to human evolution, that explains the existence of morning sickness?


A promising theory comes from Margie Profet, an evolutionary biologist (and a recipient of a 1993 MacArthur “genius” prize). In her book Protecting Your Baby-to-Be, she states that morning sickness is the result of thousands of generations of evolution, and that its purpose is to improve the survival of the human species!

Her theory is that morning sickness is Mother Nature’s way of providing humans with an instinctive toxin (or poison) avoidance mechanism. It is a biological radar, warning us when something potentially hazardous is coming our way. For thousands of years, humans were hunter-gatherers, eating whatever and whenever they could.

Many plants produce toxins designed to enhance their survival by damaging the reproductive potential of the animals that ingest them. Today, we extract many of these “toxins” and use them to our advantage, only we now call them herbs, spices, drugs, and medications!

The evidence supporting this theory is extensive. For example, fetal organ development is usually completed by week 14 of pregnancy. During those first 14 weeks, the fetus is exquisitely sensitive to the damaging effects of toxins. The first trimester is also when nearly all miscarriages occur.


About 1-3% of pregnant women experience severe morning sickness. It can lead to profound dehydration, mineral and electrolyte abnormalities, and acid-base changes in blood chemistry. Treatment requires intravenous fluids and possibly hospitalization. Contact your doctor right away if you have any of the following symptoms:

  1. Throwing up everything, food and liquids, for more than a couple of days
  2. Losing more than 5% of your body weight (e.g., a 120-lb woman loses 6 lb) compared to your prepregnant weight
  3. Feeling constantly dizzy, lightheaded, very weak, and having a dry, pasty mouth


From the evolutionary theory comes some helpful advice for dealing with morning sickness. First, trust your instinctive food aversions. If it does not smell good, look good, or “sound” good to you to eat it, then do not. Below are two lists: The “avoid” list is far more important than the “try this” list. Avoidance serves two purposes. One is to help avoid something that can aggravate the morning sickness. The other, and even more important reason, is to avoid substances potentially toxic to the first-trimester fetus.


  1. Avoid odors as much as possible. Have your partner use breath mints. No smoking in the house. Use air filters. Use odorless hygiene and laundry products. Avoid odor-filled places (crowded public places, public restrooms, smelly gyms, etc.). Have your home cleaned to try to eliminate any musty or moldy household odors. Get rid of smelly stuff in the fridge and place opened boxes of baking soda inside.
  2. Avoid unripe fruits and most vegetables (especially mushrooms), canned fruits and vegetables, greasy and high-fat foods (dairy products are usually okay).
  3. Avoid burnt foods, barbecued food, raw fish (sushi), nuts, spices, spicy foods and herbs, food flavorings, and condiments (e.g., ketchup, mustard, steak sauce) Small amounts of salt are okay.
  4. If vomiting more than once a day, stop all vitamins (yes, even prenatal vitamins) except folic acid (0.4 mg daily) and B6 (25-50 mg daily).
  5. Avoid coffee, tea, chocolate, and any substance that is bitter in its native form (before sugar and fat have been added to it).


  1. Keep saltine crackers on your nightstand. Eat one as soon as you awake, while still lying down if possible. Then wait a few minutes before getting up. The crackers will absorb stomach acid that may have accumulated during the night.
  2. Eat things a baby would like (boring, bland stuff), like plain white breads, cereal, noodles, rice, plain yogurt. Eat ripe soft fruits. Drink fresh-squeezed fruit juices ice cold and watered down a bit.
  3. Eat white cheese. It digests slowly and lessens stomach acid production. Dry, white meats like turkey breast are usually well tolerated.
  4. Drink flat, sweetened, clear soda or ginger ale (pour into a cup, then stir). If vomiting, drink Gatoradetype drinks rather than water to replace minerals. Drink liquids with crushed ice, using a straw.
  5. Eat small meals all day long, up to 10 times a day. If you have to cook, try to microwave, steam, or boil foods. This lowers the “burned food” odors.
  6. To help nausea, try the following (any medications, including vitamins and herbs, should only be taken after consulting with your doctor): vitamin B6, 50 mg once or twice a day. Try ginger, either tea or candied (helps nausea). Try lemon drops (candy). Wear wristbands, also known as acupressure or “sea” bands.


There are times when the morning sickness is so bad that without medication the patient may have to be hospitalized, or alternatively, medication may be necessary for someone to be able to leave the hospital, or for someone to function well enough not to miss work. In those cases, the benefits of using medication may outweigh the risks to the fetus. However, only a qualified obstetrician/gynecologist practitioner should make these types of decisions.


Normal (not severe) morning sickness is not a mistake at all. It is an evolutionary miracle, designed to benefit the survival of the species by reducing the risk of miscarriage and birth defects. Hopefully, the information in this article, and understanding what it means, will make dealing with morning sickness just a little bit easier.

SEE ALSO: Pregnancy, Prenatal care, Vitamins


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