Sleeping patterns vary with each child and gradually evolve over the
first year. Sleep habits are influenced by the baby's temperament and feeling
of being well fed and the parents' response to waking episodes. Some babies
naturally seem to need more sleep than others.
A newborn moves between sleeping and waking during a 24-hour day. In
the next 3 months, maturing of the brain allows the baby gradually to sleep for
longer periods. By the third or fourth month, most babies sleep for their
longest period (up to 7 to 8 hours) during the night and develop set nap
times.
Babies have sleep cycles with periods every 50 to 60 minutes of
active sleep, characterized by murmuring and restlessness. This restlessness
usually lasts a few minutes, and if babies are left alone, they usually fall
back to sleep.
The sleep cycles include:
- Drowsy sleep. The baby moves little but may be
wakened easily. His or her eyes may start to close or gently open. Drowsy sleep
can occur at the start or end of the sleep cycle.
- Quiet, or deep,
sleep. The baby moves very little; has deep, regular breathing; and has no
noticeable eye movement under the eyelids. The baby is not wakened
easily.
- Active, or light, sleep. The baby appears restless and
breathes quickly and irregularly. Eye movement is noticeable under the eyelids.
A 1-month-old may spend about 50% of her or his sleep time in active sleep,
while older children and adults spend about 20%. It is believed that a baby has
longer periods of active sleep than an adult because the brain is developing
rapidly.
At first, babies often sleep through loud noises. But, at about 3 to
4 months of age, many babies become easily disturbed by noises like the phone
ringing or a dog barking.