Stages of Fetal Development - Third Trimester

24 - 38 Weeks

Graphic for fetus at week 24
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.
Graphic for fetus at week 26
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 9 out of 10 babies born now will survive without physical or neurological impairment if they receive intensive care services.
Graphic for fetus at week 28
WEEK 28
(30 weeks after the first day of the last normal menstrual period)
  • The fetus is about 10.5 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.
Graphic for fetus at week 30
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.
Graphic for fetus at week 32
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.
Graphic for fetus at week 34
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.
Graphic for fetus at week 36
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.
Graphic for fetus at week 38
WEEK 38
(41-42 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.

Surgeon General Evelyn Griffin, MD

Secretary Bruce D. Greenstein

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