Small size

Large head relative to rest of the body

Little fat under the skin

Thin, shiny, pink skin

Veins visible beneath the skin

Few creases on soles of feet

Scant hair

Soft ears, with little cartilage

Underdeveloped breast tissue

Boys: Small scrotum with few folds; testes may be undescended in very preterm newborns

Girls: Labia majora (large lips) not yet covering labia minora (small lips) of the genitals

Rapid breathing with brief pauses (periodic breathing), apnea spells (pauses lasting 20 seconds or longer), or both

Weak, poorly coordinated sucking and swallowing reflexes

Reduced physical activity and muscle tone (a preterm newborn tends not to draw up the arms and legs when at rest as does a full-term newborn)