What is morning sickness?

Morning sickness, also called nausea and vomiting of pregnancy, is a common condition. It occurs in about 70% of pregnancies and usually starts around 6 weeks of pregnancy and lasts for weeks or months. Symptoms usually improve during the second trimester (weeks 13 to 27; the middle 3 months of pregnancy). In a few women, however, morning sickness occurs throughout their pregnancy.

Despite its name, “morning” sickness can happen at any time of the day.

Can morning sickness become severe?

Yes. Most women who experience morning sickness usually feel nauseous for a short time each day and may vomit once or twice. In more severe cases of morning sickness, nausea can last several hours each day and vomiting occurs more frequently. This most severe type of nausea and vomiting, which occurs in up to 3% of pregnant women, is called hyperemesis gravidarum.

What causes morning sickness?

The cause of morning sickness is not totally known. It may be caused by low blood sugar or the rise in pregnancy hormones, such as human chorionic gonadotropin (HCG) or estrogen. Morning sickness may be worsened by stress, being overtired, eating certain foods, or having sensitivity to motion (motion sickness).

What are the symptoms of severe morning sickness (hyperemesis gravidarum)?

Symptoms of hyperemesis gravidarum include:

  • Vomiting more than 3 times a day.
  • Becoming severely dehydrated (signs of which include little-to-no urine production, dark-colored urine, dizziness with standing).
  • Losing 5 or more pounds.

Women with severe morning sickness may need to be admitted to the hospital to receive IV fluids to restore hydration and medications to relieve nausea.

Last reviewed by a Cleveland Clinic medical professional on 06/29/2017.

References

  • The American College of Obstetricians and Gynecologists. Morning Sickness: Nausea and Vomiting of Pregnancy Accessed 6/13/2017.
  • Lee NM, Saha S. Nausea and Vomiting of Pregnancy. Gastroenterol Clin North Am 2011 June;40(2):309-34.
  • Herrell HE. Nausea and Vomiting of Pregnancy. Am Fam Physician 2014 Jun 15;89(12):965-970.

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