10.4: Overview of Developmental Milestones
- Page ID
- 167219
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| WEEK | CHANGES IN MOTHER | DEVELOPMENT OF BABY |
|---|---|---|
| Pre-embryonic Development | ||
| 1 week | Ovulation Occurs | Fertilization occurs, cell division begins and continues, chorion appears |
| Embryonic Development | ||
| 2 weeks | Symptoms of early pregnancy (nausea, breast swelling and tenderness, fatigue); blood pregnancy tests may show positive | Implantation occurs; amnion and yolk sac appear; embryo has tissue; placenta begins to form |
| 3 weeks | First period missed; urine pregnancy test may show positive; early pregnancy symptoms continue | Nervous system begins to develop; allantois and blood vessels are present and placenta is well formed |
| 4 weeks | Limb buds form; heart is beating; nervous system further develops; embryo has tail; other systems are forming | |
| 5 weeks | Uterus is the size of a hen's egg; mother may need to urinate frequently | Embryo is curved, head is large, limb buds are showing division, nose, ears and eyes are noticeable |
| 6 weeks | Uterus is the size of an orange | Fingers and toes are present and skeleton is cartilaginous |
| 8 weeks | Uterus can be felt above the pubic bone | Fetus begins to look human; limbs are developing and major organs forming; facial features are becoming refined |
| Fetal Development | ||
| 12 weeks | Uterus is the size of a grapefruit | Head grows faster than the rest of the body; facial features are apparent, but there is no layer of fat yet and the skin is translucent; gender can be distinguished via ultrasound; fingernails appear |
| 16 weeks | Fetal movement can be felt | Fine hair (lanugo) grows over the body; fetus resembles a tiny human being; skeleton is visible |
| 20-22 weeks | Uterus reaches up to the level of umbilicus and pregnancy is obvious | Vernix caseosa, the protective fatty coating, begins to be deposited; heartbeat can be heard |
| 24 weeks | Doctor can tell where baby's head, back and limbs are; breasts have enlarged and nipples and areola are darker, colostrum is produced | Fully formed but still thin; much larger and very active, all major organs are working, the lungs and digestive system need more time to develop; body is covered in fine hair called lanugo |
| 32 weeks | Uterus reaches halfway between umbilicus and rib cage | Most babies are in a head down position in the womb; head is more in proportion to the body; eyes are open; babies born at this stage have a good chance of living |
| 36 weeks | Weight gain is averaging about a pound a week; standing and walking are becoming very difficult because the center of gravity is thrown forward | Body hair begins to disappear, fat is being deposited |
| 40 weeks | Uterus is up to the rib cage, causing shortness of breath and heartburn; sleeping is very difficult | Not much room to move in the womb; fully mature, baby |