Chronological development of a baby
- 1st week (1st month)
- sex of baby is determined
- genetic traits are determined
- embryo travels from fallopian tube to the uterus.
- 2nd week (1st month)
- egg is implanted on the wall of the uterus
- placenta develops
- 3rd week (1st month)
- heart begins to develop, 18-25 days.
- brain begins to develop
- intestinal tract begins to develop
- 4th - 5th weeks (1st month)
- vertebra begins to develop
- blood flow begins
- eye development begins
- arm and leg development begins
- the umbilical cord begins to form
- 6th week (1 - 2 months)
- fingers and the toes appear
- nose, ears, develop
- joints are developing
- 7th week (1 - 2 months)
- all essential organs are developing
- eyelids form
- 8th week (2 months)
- muscle contraction occurs
- facial features become more prominent
- heart has four chambers
- 9th - 12th week (2 - 3 months)
- the baby is about 3 inches long
- the neck develops
- arms and legs begin to lengthen
- genitals are well defined
- 13th - 16th weeks (3 - 4 months)
- the baby is about 6 inches
- hair begins to develop
- the baby moves
- lungs develop
- if female, the ovaries contain about 2 million eggs
- the face is more developed
- the baby can suck its thumb
- 17th - 20th weeks (4 - 5 months)
- the baby is about 8 inches
- eyebrows form
- nails on fingers and toes form
- movement can be felt by mother
- the circulatory system is working
- swallowing
- 21st - 24th weeks (5 - 6 months)
- the baby is about 11 inches long
- the baby weighs about 1.5 pounds
- fingerprints form
- the baby can hear and react to sounds from outside the womb
- 25th - 28th weeks (6 - 7 months)
- the baby is about 15 inches long
- the baby weighs about 2.5 pounds
- survivability outside the womb is possible
- the baby can react to light from outside the womb
- 29th - 32nd weeks (7 - 8 months)
- the baby is about 16 inches long
- the baby weighs about 4.5 pounds
- all bones are fully developed
- 33rd - 40th weeks (8 - 9 months)
- the baby is about 18 - 21 inches long
- the baby weighs about 6 - 8 pounds
- the baby is ready to be born
- sleep patterns are apparent
- strong movement is very apparent
Sources:
- allhealth.com