For a pregnant woman, feeling a new life developing inside her body is an amazing experience, even though she may not always feel her best at some points along the way. Pregnancy can be different from woman to woman, and even for the same mother from one pregnancy to the next. Some symptoms of pregnancy last for several weeks or months, while other discomforts are temporary or don't affect all women. A normal pregnancy usually lasts about 40 weeks, counting from the first day of a woman's last menstrual period, which is about two weeks before conception actually occurs. Pregnancy is divided into three trimesters. Each of these periods lasts between 12 and 13 weeks. During each trimester, changes take place in a pregnant woman's body as well as in the developing fetus, and a summary of these changes will be described below. There are many factors that can affect a pregnancy. Women who receive an early pregnancy diagnosis and prenatal care are more likely to experience a healthy pregnancy and give birth to a healthy baby.Knowing what to expect during the full pregnancy term is important for monitoring both your health and the health of the baby. If you'd like to prevent pregnancy, there are also effective forms of birth control you should keep in mind.But once the final decision of keeping the pregnancy for the most beautiful reason of continuity of life and ensuring the future generation existence, the health of the mother-to-be cannot be toyed with for both the safety of her and the life she carries inside her. The type of food and other materials she ingests must be subjected to scrutiny as she goes on her 9 months journey of pregnancy and even after.Maintaining a healthy balanced diet is important for maintaining optimal health throughout life. For women of childbearing age, good nutrition is important for preparing the body for the demands of pregnancy.During pregnancy, a woman's macronutrient (energy) and micronutrient (e.g. vitamins, mineral) requirements increase, and it is even more important that she consumes food which will give her both the energy and the specific micronutrients which are essential for maintaining her and her growing baby's health. For example, women require an additional 240 calories of energy per day in the second trimester and 452 calories per day in the third trimester of pregnancy to account for foetal growth. An additional 975 milligrams of iron is required in the course of the pregnancy to form foetal and additional maternal blood.While nutritional supplements can provide large quantities of particular micronutrients, a healthy balanced diet should form the basis of a woman's nutritional intake. Good nutrition is most important immediately prior to conception and during the first 12 weeks of pregnancy (including the very early stages, when the woman is unaware she is pregnant). It is therefore important for women to maintain a healthy diet throughout their childbearing years, and particularly if they are planning to become pregnant.