What are the different stages of a fetus?

Embryonic stage (weeks 1-8)

* Week 1: The fertilized egg implants in the uterine wall.

* Week 2: The embryo forms the placenta and the amniotic sac.

* Week 3: The neural tube begins to develop.

* Week 4: The heart begins to beat.

* Week 5: The limbs begin to develop.

* Week 6: The eyes and ears begin to develop.

* Week 7: The fetus begins to move.

* Week 8: All of the major organs have formed.

Fetal stage (weeks 9-38)

* Week 9: The fetus begins to grow rapidly.

* Week 10: The fingernails and toenails begin to grow.

* Week 11: The fetus begins to produce urine.

* Week 12: The fetus begins to swallow amniotic fluid.

* Week 13: The fetus begins to move its arms and legs.

* Week 14: The fetus can hear sounds.

* Week 15: The fetus can make facial expressions.

* Week 16: The fetus begins to produce vernix caseosa, a waxy substance that protects the skin.

* Week 17: The fetus begins to hiccup.

* Week 18: The fetus can move its head from side to side.

* Week 19: The fetus can suck its thumb.

* Week 20: The fetus is fully formed and weighs about 1 pound.

21+ weeks:

* Week 21: The fetus can open its eyes.

* Week 22: The fetus can cough and sneeze.

* Week 23: The fetus can breathe on its own for short periods of time.

* Week 24: The fetus can cry.

* Week 25: The fetus can startle in response to loud noises.

* Week 26: The fetus can recognize its mother's voice.

* Week 27: The fetus can dream.

* Week 28: The fetus can suck its own fingers.

* Week 29: The fetus can turn its head from side to side.

* Week 30: The fetus can kick and punch its mother.

* Week 31: The fetus can weigh up to 3 pounds.

* Week 32: The fetus can cry tears.

* Week 33: The fetus can hiccup.

* Week 34: The fetus can start to descend into the pelvis.

* Week 35: The fetus can weigh up to 5 pounds.

* Week 36: The fetus can open its eyes and see.

* Week 37: The fetus can start to breathe on its own.

* Week 38: The fetus is ready to be born.