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.