Premature babies sleep considerably more than full-term infants, which is normal and necessary for their rapid development. This extensive rest serves a biological purpose, supporting their growth. Understanding these patterns helps parents recognize what to expect as their baby matures.
Typical Sleep Patterns of a Premature Baby
Premature babies sleep for extended periods, from 16 to 22 hours per day. Their sleep cycles are shorter than full-term infants, lasting 20 to 50 minutes. These cycles include active and quiet sleep, with preemies spending more time in active sleep. During active sleep, a baby may exhibit movements, groan, open their eyes, or have irregular breathing.
Quiet sleep is characterized by a still posture and even breathing. Premature babies wake frequently for essential feedings. Their neurological immaturity contributes to these irregular patterns. These fragmented sleep periods are a temporary phase as they mature.
The Role of Sleep in Preemie Development
Extensive sleep in premature babies is an active process that supports their development. This deep and frequent sleep aids rapid brain development, forming new neural connections and maturing white matter. Active sleep, in particular, is linked to better white matter development, which processes information and connects brain regions. Sleep also plays a role in neuronal detoxification and body temperature regulation.
Sleep periods conserve a premature baby’s energy, directing calories towards physical growth and weight gain. This is important for preemies needing to catch up on growth that would have occurred in the womb. Sleep enables the continuation of developmental processes interrupted by early birth, mimicking in-utero development. This constant state of development underscores why uninterrupted sleep is beneficial for them.
Sleep Progression and Adjusted Age
As a premature baby grows, their sleep patterns will gradually change and become more organized. To track developmental milestones, including sleep, healthcare providers use “adjusted age” instead of chronological age. Adjusted age is calculated by subtracting the number of weeks a baby was born early from their actual age since birth. For example, a baby born 10 weeks early who is now 6 months old chronologically would have an adjusted age of approximately 3.5 months.
Using adjusted age helps set realistic expectations for when a premature baby might achieve various milestones, including developing more consolidated sleep cycles. As they mature toward their original due date and beyond, their sleep cycles will lengthen, and they will begin to experience longer periods of wakefulness during the day. While full-term babies might start sleeping through the night (defined as 6-8 consecutive hours) around 4 months, a premature baby may not reach this milestone until 6 to 8 months adjusted age, or even later.
Differentiating Normal Sleepiness from Health Concerns
While premature babies sleep a lot, it is important to distinguish between normal, deep sleep and signs of potential health concerns. Normal preemie sleep allows for periods of alertness, where the baby responds to sounds and sights, and feeds well. In contrast, true lethargy indicates a change in the baby’s typical energy level or consciousness; a lethargic baby may appear drowsy, have low or no energy, and be difficult to rouse.
Parents should contact a doctor if they observe warning signs. These include difficulty waking the baby for feedings, a decrease in alertness, or poor feeding habits. Other concerning signs are changes in breathing patterns, such as rapid, slow, or noisy breathing, or pauses in breathing. A fever, a limp or floppy appearance, or persistent irritability that is difficult to soothe also warrant immediate medical attention.