One of the most exciting aspects of pregnancy, especially for first time moms, can be watching their belly grow as the pregnancy progresses. It is common for women to want to know what they should expect through the next nine months. Unfortunately, there is no set formula for the mother's belly size. Many factors can come into play from the size of the mother and baby, to the position the baby is carried in. The following are estimates based on the average experience, however, each mother's pregnancy will progress differently and her doctor should be able to ensure the baby's health throughout the process regardless of varying sizes.
Months One through Three
During the first three months, the baby begins developing a brain, spinal cord, internal organs, and skin as well as wrists, ankles, and facial features. By the end of the third month, the mother may begin to notice a small, smooth bulge above her pelvic bone.
During the fourth month, the baby begins to develop hair, lashes, and eyebrows and should be six to seven inches long and a quarter of a pound to half a pound in weight. The mother's "baby bump" may become more pronounced.
Throughout the fifth month, the baby will grow to approximately 10 to 12 ounces and about 10 inches long. This is the time when most women begin to show enough for others to notice the pregnancy.
During the sixth month, the baby reaches just over a foot long and weighs about one and a half pounds. The mother's belly will be noticeably pregnant.
By the seventh month, the baby should weigh around three pounds and measure 18 inches in length. The mother's belly will begin rapidly expanding during the coming months.
The baby is rapidly putting on weight during the final months, and will probably weigh four to five pounds by the end of the eighth month. The mother will notice her belly becoming larger and possibly affecting her mobility.
The baby will gain about half a pound a week during the last month of pregnancy. The mother may feel uncomfortable and experience increased pressure on her bladder and heartburn during the final month.