The length of your pregnancy is divided into three stages, or trimesters, each about 13 weeks long. Trimesters help group stages of development for you and your baby. Pregnancy is unique to each woman. Usually you don't have to worry if you don't look or feel exactly like another woman at the same point in pregnancy.
First trimester changes in you.
You will see very little change in yourself, although your baby is growing and changing quite rapidly. You may not even realize you are pregnant until the middle or close to the end of this trimester! You will experience very little weight gain during this time—probably no more than 5 pounds (2.25kg) for the entire 13 weeks. Your abdomen will grow a little—you may be able to feel your uterus about 3 inches (7.6cm) below your bellybutton. You won't feel the fetus move during this time.
Second trimester changes in you.
You will begin showing; others will be able to tell you are pregnant during this trimester. By the end of this trimester, you will feel your uterus about 3 inches (7.6 cm) above your bellybutton.
Average weight gain for this trimester is a total of 17 to 24 pounds (7.65 to 10.8kg), including weight from the first trimester. You will begin to feel your baby move during this time.
Third trimester changes in you.
You will experience a lot of physical change during this time because your baby will be growing so much. By delivery, your uterus is 6-1/2 to 8 inches (16.5 to 20.3cm) above your bellybutton.
Your baby will gain a great deal of weight during this time, even though you may not. Total weight gain by delivery is 25 to 35 pounds (11.25 to 15.75kg) for the average woman.
How You Look and Feel
Your body changes a lot during pregnancy. Get good prenatal care and follow your doctor's recommendations about nutrition, medication and exercise. Keep all your appointments. Establish good communication with your healthcare provider. Ask any question you have about how you look or feel.
Not showing yet.
Don't be concerned if you are about done with the first trimester and don't show yet. A lot is happening with the development of your baby's organs and organ systems, but friends probably can't tell you're pregnant. You may be able to feel your uterus down by your pubic bone, or your clothes may be getting a little snug.
If this is your first pregnancy, it often takes longer to see a change in your tummy. You may not show until your second trimester. Don't despair—you'll be getting larger soon, and then everyone will know you're pregnant! If you have had other pregnancies, you will probably show sooner.
If you have had a baby before, you may notice changes in the way your body adapts to the pregnancy this time around. The way a woman's body responds to pregnancy is influenced by her previous pregnancies. Skin and muscles stretch to
accommodate the enlarged uterus, placenta and baby. Stretched muscles and stretched skin are never exactly the same again. They may give way faster to accommodate the growing uterus and baby with subsequent pregnancies, which causes a woman to show sooner and to feel bigger. Some other reasons for looking bigger are that you are farther along than you think, or you are carrying twins.