Stages of Fetal Development - Third Trimester
Stages of Fetal Development - Third Trimester
24 - 38 Weeks
WEEK 24 (26 weeks after the first day of the last normal menstrual period)
- The fetus is about 9-inches from head to rump and weighs about 2 pounds.
- The fetus can respond to sound.
- Eyebrows and eyelashes are well formed.
- All eye parts are developed.
- The baby has developed a startle reflex.
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WEEK 26 (28 weeks after the first day of the last normal menstrual period)
- The fetus is about 10-inches from head to rump and weighs about 21/2 pounds.
- The eyes are partially open and eyelids have formed.
- About nine out of 10 babies born now will survive without physical or neurological impairment if they receive intensive care services.
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WEEK 28 (30 weeks after the first day of the last normal menstrual period)
- The fetus is about 101/2-inches from head to rump and weighs almost 3 pounds.
- The fetus has lungs that are capable of breathing air, although medical help may be needed out of the womb.
- Red blood cells are now forming in the baby’s bone marrow.
- The baby might have a full head of hair.
- The fetus can open and close its eyes, suck its thumb and cry.
- Nearly all babies born now will survive if they receive intensive care services.
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WEEK 30 (32 weeks after the first day of the last normal menstrual period)
- The fetus is about 11-inches from head to rump and weighs about 33/4 pounds.
- Although the baby’s lungs aren’t fully formed, he or she practices breathing.
- The baby’s body begins absorbing vital minerals, such as iron and calcium, from the intestinal tract.
- Almost all babies born now will live if they receive intensive care services.
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WEEK 32 (34 weeks after the first day of the last normal menstrual period)
- The fetus is about 113/4-inches from head to rump and weighs about 41/2-pounds.
- The skin is pink and smooth.
- The baby’s fingernails have reached his or her fingertips.
- Almost all babies born now will live if they receive intensive care services.
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WEEK 34 (36 weeks after the first day of the last normal menstrual period)
- The fetus is about 121/2-inches from head to rump and weighs about 51/2-pounds.
- The fetus is more round and plump.
- As the baby gets bigger, it will be harder for him or her to move around. However, she or he may stretch, roll and wiggle.
- Almost all babies born now will live.
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WEEK 36 (38 weeks after the first day of the last normal menstrual period)
- The fetus is about 131/2-inches from head to rump and weighs about 61/2 pounds.
- The fetus can grasp firmly.
- The baby’s toenails have reached the tips of his or her toes.
- The brain may weigh about 14 ounces.
- To prepare for birth, the baby may move into the head-down position.
- Almost all babies born now will live.
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WEEKS 38-41 (41 or 42 weeks after the first day of the last normal menstrual period)
- The fetus is about 14-inches from head to rump, may be more than 20 inches overall, and may weigh from 61/2 to 10-pounds.
- The baby is full-term and ready to be born.
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