T/F: A newborn male, estimated to be 39 weeks of gestation, would exhibit a moderate amount of lanugo over his entire body.
F: The newborn will exhibit only a moderate amount of lanugo, usually on his shoulders and back.
During human development, the lanugo grows on fetuses as a normal part of gestation, but is usually shed and replaced by vellus hair at about 33 to 36 weeks of gestational age. As the lanugo is shed from the skin, it is normal for the developing fetus to consume the hair with the fluid, since it drinks from the amniotic fluid and urinates it back into its environment. Subsequently, the lanugo contributes to the newborn baby's meconium. The presence of lanugo in newborns is a sign of premature birth.
A hypothesis, according to the NHS, is that the lanugo of human fetuses has to do with temperature regulation.