Nausea and vomiting during the first trimester of pregnancy, also called morning sickness, can be signs of a healthy pregnancy. A study of more than 2,400 pregnant women associated nausea and vomiting during the first trimester with a reduced risk of early pregnancy loss — particularly for women age 30 and older.
Shortly after a fertilized egg attaches to your uterine lining, your body begins to produce a hormone called human chorionic gonadotropin (HCG). While the cause of nausea during pregnancy isn't clear, nausea typically begins when production of HCG begins. As a result, nausea during pregnancy might indicate that you're experiencing the normal climb in pregnancy hormones needed for a healthy pregnancy.
Other theories suggest that nausea during pregnancy might:
- Reduce fetal exposure to potentially dangerous substances in your diet
- Encourage you to eat foods that contain certain nutrients, such as those rich in carbohydrates
- Prompt you to adjust your activity level to favor maternal and fetal tissue growth
A lack of nausea during pregnancy, however, isn't necessarily a cause for concern. Some women don't seem to experience common symptoms of early pregnancy despite the generous production of pregnancy hormones. Also, nausea can sometimes signal a problem. For instance, severe nausea and vomiting can indicate a molar pregnancy — when the placenta develops into an abnormal mass of cysts rather than becoming a viable pregnancy — or hyperemesis gravidarum, a condition that causes you to lose weight and body fluids and might require treatment with intravenous fluids and medications.
If you're concerned about morning sickness or wonder whether your morning sickness is normal, consult your health care provider.