Morning sickness is nausea that occurs during pregnancy. Morning sickness affects a large proportion of pregnant women. It is most common during the first trimester. Some women have nausea and vomiting through their entire pregnancy. Hormonal changes of pregnancy are thought to play a role. Changes include rapidly increasing oestrogen levels, an enhanced sense of smell, excess stomach acids, and increased fatigue. Some researchers think that stress and emotions also play a part in morning sickness.
Rarely, severe or persistent nausea or vomiting may be caused by a medical condition unrelated to pregnancy such as thyroid or liver disease. Treatment isn't necessary for most cases of morning sickness. If your morning sickness symptoms persist, however, your pregnancy care provider may prescribe vitamin B-6 supplements, antihistamines and possibly anti-nausea medications. About half of the women who get nausea during pregnancy feel complete relief by about 14 weeks. There is tentative evidence that ginger may be useful; however, it is not clear. Safety concerns have been raised regarding its anticoagulant properties.