What causes morning sickness (nausea and vomiting during pregnancy)?
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No one knows for sure what causes the nausea and vomiting. Increasing levels of hormones may play a role. Hormonal changes also may heighten your sense of smell and make you much more sensitive to certain odors. These changes can cause your sense of taste to be “off”—you may have a sour or bitter taste in your mouth, or nothing may taste good to you.
See Morning Sickness: Nausea and Vomiting of Pregnancy to learn more.
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Published: October 2020
Last reviewed: October 2020
Copyright 2020 by the American College of Obstetricians and Gynecologists. Read copyright and permissions information.
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