Prenatal Development

conception to 4 wks.: Beginning development of spinal cord, nervous system, GI system, heart, and lungs

8 wks.: Arms and legs are moving, brain and face is forming, fetal heartbeat detectable with ultrasound

12 wks.: can move arm, legs, fingers, and toes, sex is distinguishable

16 wks.: heartbeat is strong, lanugo, has coordinated movements

20 wks.: heartbeat is audible with stethoscope

24 wks.: skin is wrinkled and covered with vernix, waste matter is collected in bowel

(after 24 wks. baby has a higher chance of survival if born)

28 wks.: very active, rudimentary breathing movements

32 wks.: has periods of sleep and wakefulness, responds to sounds, may assume birth position

36-38 wks.: thick vernix, less active, lanugo mostly gone, gaining immunities from mom