Morning sickness is nausea, sometimes with vomiting, caused by hormones released by a woman's body during pregnancy. Morning sickness occurs most often during the first three months of pregnancy.
Some women find that nausea and vomiting are worst in the morning. But symptoms can occur at any time of the day or night. Most women feel better at the beginning of the second trimester. But some continue to feel ill throughout their pregnancies.
eMedicineHealth Medical Reference from Healthwise
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