Fetal Development
A Baby's First 25 Weeks of Life
Day 1 conception takes place.
7 days tiny human implants in mother’s uterus.
10 days mother’s menstruation cycle stops.
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 system begin to form.
42 days brain waves recorded, skeleton complete, reflexes present.
7 weeks can suck his/her thumb. *Two thirds of abortions happen
within the 1st trimester. This means the baby feels the pain!*
8 weeks all body systems present.
9 weeks squints, swallows, moves tongue, makes fist.
11 weeks spontaneous breathing movements, has fingernails, all body
systems working.
12 weeks weighs one ounce.
16 weeks genital organs clearly differentiated, grasps with hands,
swims, kicks, turns, somersaults.
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 56% of babies survive premature birth.*
25 weeks 79% of babies survive premature birth.*
(*Source: M. Allen et. al., "The Limits of Viability." New England Journal of Medicine. 11/25/93: Vol. 329, No. 22, p. 1597.)