Because folic acid plays a role in normal cell division, its intake is important during pregnancy for the rapidly dividing embryonic cells. Consuming sufficient folate before and during early pregnancy can help prevent neural tube defects such as spina bifida and anencephaly and can reduce the incidence of congenital heart disease. A deficiency of folate can occur when the body's need for folate is increased, when dietary intake of folate is inadequate, or when the body excretes (or loses) more folate than usual. The health belief model is a popular model applied in nursing, especially in issues focusing on patient compliance and preventive health care practice. The health belief model addresses the relationship between a person's beliefs and behavior. It provides a way to understand and predict how clients will behave in relation to their health and how they will comply with health care therapies. Nursing has evolved over the centuries, moving from the Nightingale Era of caring for the sick to the Healthy People Era, which in turn promotes health and wellness. Nurses today are equally involved in the role of a health promoter and illness preventer as well as a problem solver.