About Morning Sickness


Pregnant women often suffer from nausea with or without vomiting in their first trimester, a condition we know as morning sickness. Although certainly unpleasant, in most cases morning sickness has no harmful effects on you or your baby. It will probably disappear later in your pregnancy and in the meantime you can try several strategies to minimize it.

Time Frame

The nausea of morning sickness peaks in the morning for most pregnant women, but symptoms can strike at any time. According to the “Essential Guide for Pregnancy and Birth,” 75 percent of pregnant women suffer morning sickness in the first trimester. Symptoms can start as early as four weeks, but for most women symptoms begin at about six weeks. For about half of pregnant women, morning sickness ends at about the 14th week.


The presence or absence of morning sickness does not necessarily mean anything about the health of your pregnancy. Although women who eventually miscarry have a lower incidence of morning sickness, its absence should not alarm you if you have no other reason to suspect a problem with your pregnancy.

No one knows exactly what causes morning sickness, but pregnancy hormones affect several factors that can provoke nausea. Increased levels of progesterone heighten your sense of smell, make you more sensitive to noxious odors and make your stomach more sensitive.

Risk Factors

You are more likely to experience morning sickness if before your pregnancy birth control pills made you nauseated or if you had migraines or suffered from motion sickness. If your mother or sister had morning sickness, if you had morning sickness in a previous pregnancy, or if you are pregnant with twins (or more), your risk of morning sickness increases.


Nothing can prevent morning sickness, but you can try several strategies to minimize the nausea. A completely empty stomach aggravates nausea, so eat small meals and snack throughout the day. Avoid fatty foods because they take longer to digest. Eat your meals cold or at room temperature to cut down on odors that might upset your stomach. Ginger fights nausea, and you can grate some into hot water or sip on ginger ale made with real ginger.

With your doctor’s permission, you can try over-the-counter drugs to suppress vomiting or fight acid reflux. High doses of vitamin B6 might help, but again, ask your doctor’s permission first.


Rarely, morning sickness becomes so severe that it threatens your health, a condition called hyperemesis gravidum. If you cannot keep anything down for 24 hours, including juice or water, go to the emergency room. Dehydration, malnutrition or metabolic imbalances can harm you or your baby.

About this Author

In 20 years as a biologist, Susan T. McClure has contributed articles to scientific journals such as “Nature Genetics” and “American Journal of Physiology.” She earned her Ph.D. from the University of Maryland. She enjoys educating people about science and the challenge of making complex information accessible.