How does a foetus develop? Take a look at this timeline for more information.
First trimester (months 1-3)
- Day 1 – conception takes place.
- 7 days – tiny human implants in mother’s uterus.
- 10 days – mother’s periods stop.
- 18 days – heart begins to beat.
- 21 days – pumps own blood through separate closed circulatory system with own blood type.
- 28 days – eye, ear, and respiratory systems begin to form.
- 42 days – brain waves recorded, skeleton complete, reflexes present.
- 7 weeks – photo of thumb sucking.
- 8 weeks – all body systems present.
- 9 weeks – squints, swallows, moves the tongue, makes a fist.
- 11 weeks – spontaneous breathing movements, has fingernails, all body systems working.
- 12 weeks – weighs one ounce.
Second trimester (months 4-6)
- 16 weeks – genital organs clearly differentiated, grasps with hands, swims, kicks, turns, somersaults (may now be felt by the mother)
- 18 weeks – vocal cords work – can cry.
- 20 weeks – has hair on head, weighs one pound, 12 inches long
- 23 weeks – 15% chance of viability outside of womb if birth premature
- 24 weeks – current legal limit for abortion
Third trimester (months 7-9)
- 24 weeks – 56% of babies survive premature birth.
- 25 weeks – 79% of babies survive premature birth.
- 37 weeks – pregnancy classed as full term
This information is taken from the BBC Health website.