Morning sickness is nausea and vomiting that can actually occur at any time of the day during pregnancy.

See also:

• Hyperemesis gravidarum
• Pregnancy care

Morning sickness is very common. Most pregnant women have at least some nausea, and about a third have vomiting. Morning sickness usually begins during the first month of pregnancy and continues through the 14th to 16th week (3rd or 4th month). Some women have nausea and vomiting through their entire pregnancy.

Morning sickness does not hurt the baby in any way unless you lose weight, such as with severe vomiting. The amount of morning sickness during one pregnancy does not predict how you will feel in future pregnancies.

The exact cause of morning sickness is unknown. It may be caused by hormone changes or lower blood sugar during early pregnancy. Emotional stress, fatigue, traveling, or some foods can make the problem worse. Nausea in pregnancy is more common and can be worse with twins or triplets.