Newborns have irregular sleep cycles - Their circadian rhythms are not yet fully developed, causing them to sleep in shorter bursts throughout the day and night.

Hunger drives nighttime wakings - Infants need to feed every 2-3 hours, which often disrupts their sleep as they wake up hungry.

Also worth reading: How can I make comments scroll through smoothly on my website? · How can I use LaTeX in Gmail through a userscript for better formatting? · Is it common for people to display affection towards dogs through kisses, and are there any potential benefits or drawbacks to doing so?

Separation anxiety peaks around 8-12 months - Babies can have trouble falling and staying asleep when they become anxious about being separated from their caregivers.

Discomfort from teething - The pain and discomfort of teething can make it difficult for babies to sleep soundly through the night.

Sensitivity to noise and light - Babies have heightened senses and can be easily woken by noises or bright lights in their sleeping environment.

Developmental leaps - During key developmental stages, babies experience cognitive and physical changes that can disrupt their sleep patterns.

Inconsistent bedtime routines - Establishing a consistent bedtime routine is crucial for helping babies learn to self-soothe and sleep through the night.

Difficulty regulating body temperature - Babies have a harder time maintaining a comfortable body temperature, which can wake them up.

Nightmares and night terrors - As early as 18 months, children can experience these sleep disturbances that interrupt their sleep.

Underlying medical issues - Conditions like reflux, allergies, or sleep apnea can contribute to disrupted sleep in young children.

Overtiredness - Keeping children up too late in an attempt to get them to sleep longer can backfire, leading to a more fragmented sleep.

Genetics - Some children are simply predisposed to lighter, more fragmented sleep patterns due to inherited traits.

Lack of self-soothing skills - Babies who rely on being rocked or nursed to sleep may struggle to fall back asleep on their own when they wake during the night.

Environmental changes - Disruptions to a child's usual sleeping environment, such as travel or daycare transitions, can disrupt their sleep patterns.