Morning sickness is the nausea and vomiting that some women have when they become pregnant.
It is caused by the sudden increase in hormones during pregnancy. Although morning sickness is more common in the morning, it can last all day for some women. Morning sickness is very common early in a pregnancy. But there isn't a set time to say it will stop because each woman is different, and each pregnancy is different. Morning sickness can become more of a problem if you can't keep any foods or fluids down and begin to lose a lot of weight.