Morning sickness refers to 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. It tends to go away later in pregnancy, and it's almost always gone by the second trimester (the fourth month). But there isn't a set time for it to 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. Many doctors think morning sickness is a good sign because it means the it means the placenta and fetal membranes is developing well.The tips below may help reduce morning sickness.Eat small meals throughout the day so that you're never too full or too hungry.Avoid rich, fatty foods.Avoid foods with smells that bother you.Curd rice, idlis and any steamed items.The best medication is to keep changing places. The new environment might help you for a time and again patients have to find another place and it goes on and on.