Some will be lucky enough to never experience this sickness. It's thought that it's caused by a change in hormones. Some will experience it only after eating certain foods, or after taking their prenatal vitamin. Others may experience it if they allow their stomachs to become empty.
These are a few remedies for combating the nausea:
All foods / drinks need to be consumed in small portions. Get plenty of rest and drink plenty of water to stay hydrated.
With some women the sense of smell can trigger the nausea. If you find that certain odors cause you to feel sick, try to avoid being around these smells until the sickness passes.
There are times when morning sickness becomes so bad that it warrants medical attention. If you are so sick that you are unable to keep down water and food and are loosing weight you need to seek help. If you vomit more than 4 times per day, this is not normal. There are prescribed medications that help with the nausea.
Listen to your body, if you feel tire, stop and rest. If you are thirsty, stop and drink water. If you feel hunger, eat a small portion of food. Bottom line is that you need take it easy during pregnancy.