Here's a month-by-month guide to your baby's development:
- Tiny limb buds, which will grow into arms and legs, appear.
- The embryo looks like a tadpole.
- The heart and lungs begin to form. By the 25th day, the heart starts to beat.
- The neural tube, which becomes the brain and spinal cord, begins to form.
- At the end of the first month, the embryo is about 1/2 inch long and weighs less than 1 ounce.
- All major body organs and systems are formed but not completely developed.
- The early stages of the placenta, which exchanges nutrients from your body for waste products produced by the baby, are visible and working.
- The ears, ankles, and wrists form. The eyelids form and grow but are sealed shut.
- Fingers and toes develop.
- By the end of the second month, the fetus looks more like a person than like a tadpole, is about 1 inch long and still weighs less than 1 ounce.
- After 8 weeks as an embryo, the baby now is called a "fetus."
- The fingers and toes have soft nails.
- The mouth has 20 buds that will become "baby teeth."
- You can hear your baby's heartbeat for the first time (10 to 12 weeks) using a special instrument called a Doptone.
- For the rest of pregnancy, the body organs will mature, and the fetus will gain weight.
- By the end of this month, the fetus is 2 1/2 inches long and weighs a little over 1 ounce.
- The fetus moves, kicks, and swallows.
- The skin is pink and transparent.
- The umbilical cord continues to grow and thicken to carry enough nourishment from mother to fetus.
- The placenta is fully formed.
- By the end of the fourth month, the fetus is 6 to 7 inches long and weighs about 5 ounces.
- The fetus becomes more active, turning from side to side and sometimes head over heels.
- The fingernails have grown to the tips of the fingers.
- The fetus sleeps and wakes at regular intervals.
- The fetus has a month of rapid growth. At the end of the fifth month, the fetus is 8 to 12 inches long and weighs 1/2 to 1 pound.
- The skin is red and wrinkled and covered with fine, soft hair.
- The eyelids begin to part and the eyes open.
- The finger and toe prints can be seen.
- The fetus continues its rapid growth. At the end of the sixth month, the fetus is 11 to 14 inches long and weighs 1 to 1 1/2 pounds.
- If born now, the fetus might survive with intensive care.
- The fetus can open and close its eyes and suck its thumb.
- The fetus exercises by kicking and stretching.
- The fetus responds to light and sound.
- If born now, the fetus has a good chance for survival.
- The fetus is now about 15 inches long and weighs about 3 pounds.
- Rapid brain growth continues.
- The fetus is too big to move around much but can kick strongly and roll around.
- You may notice the shape of an elbow or heel against your belly.
- The bones of the head are soft and flexible to make it easier for the baby to fit through the birth canal.
- The lungs may still be immature. If born now, before 37 weeks, the fetus is premature but has an excellent chance for survival.
- The fetus is now about 18 inches long and weighs about 5 pounds.
- At 37 to 40 weeks, your baby is full term.
- The baby's lungs are mature and ready to work on their own.
- During this month the baby gains about 1/2 pound a week.
- The baby moves into position to be born, usually dropping into a head-down position and resting lower in the mother's belly.
- By the end of the ninth month, the baby weighs 6 to 9 pounds and is 19 to 21 inches long.