Burns and Grove (2003:213) describe population as all the elements that meet the criteria for inclusion in a study. Burns and Grove (2003: 234) define eligibility criteria as âa list of characteristics that are required for the membership in the target populationâ.
Nausea is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It may precede vomiting, but a person can have nausea without vomiting. When prolonged, it is a debilitating symptom. Nausea is a non-specific symptom, which means that it has many possible causes. Some common causes of nausea are motion sickness, dizziness, migraine, fainting, gastroenteritis (stomach infection) or food poisoning. Nausea is a side effect of many medications including chemotherapy, nauseants or morning sickness in early pregnancy. Nausea may also be caused by anxiety, disgust and depression.
What causes morning sickness isn't clear, but the hormonal changes of pregnancy are thought to play a role. Rarely, severe or persistent nausea or vomiting may be caused by a medical condition unrelated to pregnancy â such as thyroid or liver disease. 1  Symptoms. 2  Risk factors.