During the last three months of a pregnancy, or the third trimester, the baby grows rapidly, reaching three or four times its previous weight. As the baby grows larger, the mother may experience some discomfort from the pressure on her stomach or bladder. She'll feel the baby's stronger and more frequent movements. Now's the time to start preparing herself and her home for the baby's arrival. In the seventh month, the baby averages 13 to 15 inches long, and weighs about one and a half to three pounds. It exercises by kicking and stretching, and changing position from side to side. Some of these movements can even be seen outside the womb. The mother may gain another three or four pounds this month, and may also notice some slight swelling in her ankles. A slight amount of swelling is normal. In the eighth month, the baby has grown to about 16 inches long, weighing close to four pounds. The eyes are open, and the baby changes position in the uterus. This position is maintained until the baby is born. During this month, the mother may gain three to five pounds. She can continue her daily activities, but with more frequent rest periods. Any heavy lifting or work that causes strain should be avoided. Whenever possible, she should sit with her legs and feet elevated. In the ninth month, the baby's weight gain is about half a pound per week. At 40 weeks, the baby is 'full-term' and weighs from six to nine pounds. It settles further down into the mother's pelvis into a position known as 'dropped.' This new position may make mother feel more comfortable and ease her breathing, although she may need to urinate more frequently. Mothers should visit their doctor every week until the baby is born. For more information about fetal development in the third trimester, contact a health care professional.