Conception

• The sperm fertilizes the egg or ovum. An embryo forms. Traveling down the fallopian tube, more cells begin to develop. The uterine wall receives the embryo where it will continue to grow.
  
  

Nine Weeks

• The embryo has a beating heart, toes and fingers. It also has developing lungs, arms, legs and facial features.
  
  

Fourteen Weeks

• The embryo is now classified as a fetus. It is 6 inches in length. A chin and a nose may be seen on an ultrasound examination.
  
  

Twenty-Four Weeks

• The baby has been moving since the 20th week. The fetus is able to see light and hear noise now. The heart can be heard with a stethoscope. Approximate size is 2 pounds, 11 inches. Survival rate if born is 50 per cent.
  
  

Thirty-Four Weeks

• At 27 weeks, survival rate increases to 85 percent. The lungs are mature. Approximate length of the fetus is 18 to 20 inches.
  
  

Full-Term

• The baby is born between week 37 and week 42.