Morning Sickness

The existence of morning sickness early in pregnancy seems extremely unfair! 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 should be called "all-day" sickness

For many pregnant women, morning sickness should be called all-day sickness. The preferred term is pregnancy sickness. It is awful! It can range in severity from none (20% of all pregnant women don't get it) to persistent vomiting so severe that hospitalization and treatment with intravenous fluids are needed to save the patient's life. Usually, it is a constant feeling of nausea, like you are about to throw up, along with an incredible sensitivity to all odors, such that even a whiff of something you thought that you loved can set off another bout of nausea and/or vomiting.

Why does morning sickness exist at all? - Traditional explanation

Doctors used to be taught that morning sickness was psychological, a sign that the patient is ambivalent about being pregnant. This theory is a bunch of baloney, and I refuse to discuss it further.

Many articles link morning sickness to the pregnancy hormone hCg. Morning sickness tends to be worse with multiple gestation (a high hormone state) and it tends to be minimal in pregnancies which end in miscarriage (a low hormone state). I tell patients that it may not make any sense, but the sicker they are, the "better" the pregnancy. This theory doesn't explain everything however. The key question to me is - "Why do normal, healthy pregnant women get so sick?"

An evolutionary explanation

The best theory I have seen to explain morning sickness comes from Margie Profet, an evolutionary biologist (and a recipient of a 1993 MacArthur "genius" prize). In her book, Protecting Your Baby-to-Be (Addison-Wesley, 1995) she states that morning sickness is the result of thousands of generations of evolution, and that it's purpose is to improve the survival of the human species!

Morning sickness is Mother Nature's instinctive toxin avoidance mechanism. It is our 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. (For example, the plant lupine produces a reproductive toxin so severe that if a pregnant animal even drinks the milk from another animal that has grazed on lupine, the litter will be born with severe bone abnormalities, scoliosis, cleft palate and malformed limbs.) 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. Nearly all cases of morning sickness resolve by the end of week 14!

Severe morning sickness

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:

  • Throw up everything, food and liquids, for more than a couple of days.
  • Losing more than 5% of your body weight (for example a 120 lb. woman loses 6 pounds) compared to your pre-pregnant weight.
  • Feeling constantly dizzy, lightheaded, very weak and you have a dry, pasty mouth.

Management of mild morning sickness

From the evolutionary theory comes some helpful advice for dealing with morning sickness. First, trust your instinctive food aversions. If it doesn't smell good, look good, or "sound" good to you to eat it, then don't. 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 1st trimester fetus!

Things to avoid 

  1. Avoid odors as much as possible. Have your husband take breath mints. Use odorless hygiene and laundry products. Avoid odor-filled places (crowded public places, public restrooms, smelly gyms, etc.). Have your home cleaned to try and 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), and canned fruits and vegetables. 
  3. Avoid greasy and high-fat foods (dairy products are usually okay). 
  4. Avoid burnt foods. Avoid barbecued food. 
  5. Avoid raw fish (sushi) and avoid nuts. 
  6. Avoid spices, spicy foods and herbs: garlic, onion, dill, oregano, etc. 
  7. Avoid food flavorings and condiments: ketchup, mustard, steak sauce, etc. Small amounts of salt are okay. 
  8. If vomiting more than once a day, stop all vitamins (yes, even prenatal vitamins) except folic acid (0.4 mg. daily) and B-6 (25-50 mg. daily). 
  9. Avoid Emmetrol, a children's anti-nausea agent (often advised to help morning sickness). It is safe but in my experience never works, and often makes patients throw up even more. 
  10. Avoid coffee, tea, chocolate, and any substance which is bitter in it's native form (before sugar and fat have been added to it).

Things to try

  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. 
  3. Eat ripe soft fruits. Drink fresh-squeezed fruit juices, ice cold and watered down a bit. 
  4. Try a blender-shake made with ice, plain yogurt or milk, and ripe fruit or fresh fruit juice. Whey or soy protein powder can be added if your diet is low in protein. 
  5. Eat white cheese. It digests slowly and lessens stomach acid production. 
  6. Dry, white meats like turkey breast are well tolerated. 
  7. Drink flat Seven-up or Sprite (pour into a cup, then stir). 
  8. If vomiting, drink Gatorade-type drinks rather than water to replace minerals 
  9. Drink liquids with crushed ice, using a straw. 
  10. Eat small meals all day long, up to 10 times a day. 
  11. If you have to cook, try to microwave, steam or boil foods. This lowers the "burned food" odors. 
  12. To help nausea, try the following: Vitamin B-6, 50 milligrams once or twice a day. Try ginger, either tea or candied (helps nausea). Try Atomic Fireball candy (one patient swears they help). Or lemon drops. Wear wrist bands, also known as acupressure or "sea" bands. (Personally, I think they are a waste, but when you feel so lousy, anything harmless is probably worth a try).

What if you don't have any morning sickness?

Assuming that the pregnancy is healthy, I would strongly advise following the suggestions in the "avoid" list. If morning sickness is really designed to prevent toxins from reaching the unborn baby, not having morning sickness may theoretically cause more harm than good.

Using Medication

As a physician, there are times where 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 the medication are felt to outweigh the risks to the fetus. However, only a qualified ob/gyn practitioner should make these types of decisions.


To learn more, I highly recommend Margie Profet's book. It has helped me to finally understand what has always bothered me (and really bothered so many of my patients). Normal (not severe) morning sickness isn't unfair after all. It is an evolutionary miracle, designed to benefit the survival of the species by reducing the risk of miscarriage and birth defects. I hope that the information in this article, and understanding what it means will make dealing with your morning sickness just a little bit easier.

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