The main reason why morning sickness occurs on women is because they are experiencing hormonal changes in their body. This is caused by pregnancy so be prepared It is believed that morning sickness is the most common term that describes nausea which usually comes or happens during the first two to three months of pregnancy. There is no particular time when morning sickness will occur, only morning sickness remedies that can help. What you don’t’ want to happen is to experience it the whole day because the feeling could make you feel weak and could make you stay all day on your bed resting.