| A | B |
|---|
| 1st month | spinal cord and nervous system start to develop |
| 1st month | embryo is about 1/4 inch long |
| 2nd month | embryo is now called a fetus; face and sex organs develop |
| 2nd month | bones are being formed |
| 3rd month | fingernails, toenails, hair follicles and eyelids appear |
| 3rd month | sex organs become recognizeable |
| 4th month | face is formed; hair begins to grow |
| 5th month | heartbeat can be heard through a stethescope |
| 6th month | fetus shifts position to head down; fetus about 1 ft long |
| 7th month | central nervous system develops so baby can live if is born now |
| 8th month | fat deposits are forming under skin; nails and bones are hardening. |
| 8th month | lungs are maturing |
| 9th month | rapid weight gain every day until birth |
| 9th month | cartilage in nose and ears develops; fetus 18 inches long and weighs about 5.5 lbs |
