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.
For some women, morning sickness lasts all day. The exact cause of morning sickness is not known. 1  Most experts think changes in the woman's hormone levels during pregnancy cause it. 2  Other factors that can make the nausea worse include a pregnant woman's enhanced sense of smell and gastric reflux.