| A | B |
|---|
| conception | occurs when sperm and egg meet in the Fallopian tube |
| fertilization | fertilized egg attaches itself to wall of the uterus |
| 1st month or 4 weeks | heart starts to beat |
| 1st month or 4 weeks | embryo is about 1/4 inch long |
| 2nd month or 8 weeks | embryo is called a fetus |
| 2nd month or 8 weeks | face and sex organs develop; bones are being formed |
| 3rd month or 12 weeks | fingernails, toenails, and hair follicles appear |
| 3rd month or 12 weeks | sex organs are recognizeable |
| 4th month or 16 weeks | face is formed; looks like a baby |
| 4th month or 16 weeks | hair begins to grow |
| 5th month or 20 weeks | heartbeat may be heard through a stethoscope |
| 5th month or 20 weeks | fetal movement can be felt |
| 6th month or 24 weeks | fetus position shifts to head down |
| 6th month or 24 weeks | fetus can hear noises |
| 7th month or 28 weeks | central nervous system develops so if baby is born now it can survive |
| 8th month or 32 weeks | nails and bones are hardening |
| 8th month or 32 weeks | lungs are maturing |
| 9th month or 36 weeks | rapid weight gain |
| 9th month or 36 weeks | fetus weighs about 5.5 lbs |
| birth | 19-21 inches long; breathes air for the first time on its own |
