Medical Definition of Morning sickness

Morning sickness: Nausea and vomiting of pregnancy.

Morning sickness is a misnomer, because it can occur at any time of the day (though not at night during sleep) and it is not a sickness. It is a normal characteristic of early pregnancy.

Morning sickness is now believed to be a good thing since it appears associated with a reduced risk of miscarriage and a greater chance that the pregnancy will have a healthy outcome.

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