Pregnancy consists of three stages, also called pregnancy trimesters. Each trimester is composed of three months. These three trimesters are a means by which the entire process of forty weeks is classified into distinct stages in which both the fetus and the mother experience considerable changes.
...During this time, the mother experiences changes in her body, such as increase in the size of the breasts. She also experiences morning sickness and menstruation may be very light or may not occur at all. Other symptoms of this stage include tenderness in the breasts, aversions to certain foods, heartburn, constipation and dizziness. For the fetus, major changes take place inside the womb. The vital organs begin to form and during this time the fetus is very vulnerable to damage from drugs, illness or medications taken by the mother. For the initial eight weeks of the first trimester, the fetus is referred to as an embryo. This embryo grows very fast and when the first trimester ends, it is known as a fetus and weighs around one ounce and measures about three inches in length.
The second trimester of pregnancy lasts till the seventh month and is a relatively easier stage for the mother as she begins to gain back her energy. As the fetus grows and develops, the mother’s abdomen will swell. The skin over this area starts stretching and stretch marks may develop. The mother will also begin to feel the movements of the fetus. This generally occurs somewhere between the sixteenth and twentieth week and is known as quickening. There may be changes in complexion and the areola of the breasts begins to darken. Several other symptoms may be experienced by the mother such as congestion, increased appetite, backache, cramping in the legs and contractions of the uterus. The fetus continues to grow rapidly and eyebrows and fingernails develop. The fetus may also kick at this time. All the organs have developed by now and the fetus starts to gain in weight and size.
The third trimester of pregnancy is the last stage and runs through the twenty-eight week until the fortieth week. The fetus increases in size and the systems of its body mature. The mother gains more weight and may experience false labor contractions. The mother may spend this time in preparing for childbirth. As the fetus grows to its full size now, the abdominal cavity is stretched considerably. As such many mothers may feel uncomfortable while sleeping or moving around. At the end of the third trimester, the baby is born.