Prenatal Development

Conception to 4 weeks

Beginning development of spinal cord, nervous system, GI system, heart, and lungs.

8 weeks

Arms and legs are moving, brain and face are forming, fetal heartbeat detectable with ultrasound.

12 weeks

Can move arms, legs, fingers, and toes; sex is distinguishable.

16 weeks

Heartbeat is strong, lanugo present, has coordinated movements.

20 weeks

Heartbeat is audible with a stethoscope.

24 weeks

Skin is wrinkled and covered with vernix; waste matter is collected in the bowel.

After 24 weeks

Baby has a higher chance of survival if born.

28 weeks

Very active, rudimentary breathing movements.

32 weeks

Has periods of sleep and wakefulness; responds to sounds; may assume birth position.

36-38 weeks

Thick vernix, less active, lanugo mostly gone, gaining immunities from mom.