SIDS Risk Factors and Safe Sleep
The short answer
SIDS is the unexplained death of a baby under 1 year old during sleep. While the exact cause remains unknown, the risk can be significantly reduced by following safe sleep practices: always place your baby on their back, on a firm flat surface, with no loose bedding, pillows, bumpers, or toys. The ABCs of safe sleep are Alone, on their Back, in a Crib. Room-sharing without bed-sharing for at least the first 6 months reduces SIDS risk by up to 50 percent.
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By Age
What to expect by age
0-1 month
Place your newborn on their back for every sleep, including naps. Use a firm, flat mattress in a safety-approved crib, bassinet, or play yard with nothing else in the sleep space. No blankets, pillows, crib bumpers, stuffed animals, or sleep positioners. Dress your baby in a sleep sack or wearable blanket rather than loose covers. Room-sharing (but not bed-sharing) is recommended for at least the first 6 months. Having your baby's sleep space in your room makes nighttime feeding easier and has been shown to reduce SIDS risk significantly.
1-4 months
This is the period of highest SIDS risk. Most SIDS deaths occur between 1 and 4 months of age. Maintain a safe sleep environment for every sleep. Offer a pacifier at nap time and bedtime - research shows pacifier use is associated with reduced SIDS risk, even if it falls out after your baby falls asleep. Avoid overheating - signs include sweating, damp hair, flushed cheeks, or a chest that feels hot. Dress your baby in one layer more than what an adult would find comfortable.
4-6 months
SIDS risk begins declining after 4 months but remains present. Some babies start rolling during this period. If your baby rolls from back to tummy on their own during sleep, you do not need to reposition them, as long as you always place them on their back initially and the sleep space is free of hazards. Stop swaddling once your baby shows signs of rolling. Transition to a sleep sack with arms free.
6-12 months
While most SIDS cases occur before 6 months, it can still happen up to 12 months. Continue safe sleep guidelines throughout the first year. By this age babies roll freely and may choose their own sleep position. As long as you place your baby on their back at the start of sleep and the crib is clear, you do not need to worry if they roll. Do not introduce pillows, blankets, or stuffed animals before 12 months.
12-36 months
After the first birthday, SIDS risk drops dramatically. You can introduce a thin blanket and small firm pillow after 12 months if desired. Continue to avoid large suffocation hazards. If transitioning to a toddler bed, ensure the bedroom is child-proofed. Risk factors for sleep-related deaths in toddlers include entrapment between the mattress and wall, strangulation from cords, and falls.
What Should You Do?
When to take action
- Your baby occasionally turns their head to one side while sleeping on their back
- Your baby who can roll independently prefers sleeping on their stomach after being placed on their back
- Your baby startles or makes brief grunting sounds during sleep - these are normal infant sleep behaviors
- You feel anxious about SIDS even though you are following all safe sleep recommendations - this worry is completely normal for parents
- You have questions about transitioning out of a swaddle or which sleep sack to use
- Your baby has a sibling or close family member who died of SIDS, as there may be a slightly increased risk
- Your baby was born premature or at low birth weight, which are additional risk factors
- You find your baby unresponsive, not breathing, or limp during sleep - call 911 immediately and begin infant CPR if trained
- Your baby has had an apparent life-threatening event where they stopped breathing, turned blue or pale, or became limp - seek emergency evaluation
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
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Related Medical Concerns
My Baby Rolls Face Down in Sleep
Once your baby can roll from back to tummy and tummy to back independently, it's safe to let them find their preferred sleep position, even if it's face down. Always place your baby on their back to start sleep, but if they roll over on their own, you don't need to keep repositioning them.
Co-Sleeping Safety - Risks and Guidelines
The AAP recommends room-sharing (baby sleeps on their own surface in the same room) but not bed-sharing for the first year. Bed-sharing increases the risk of SIDS and suffocation, especially in the first 4 months, with premature babies, when parents smoke, drink, or take sedating medications, and on soft surfaces. Many families do end up bed-sharing at some point - if you choose to or find yourself doing so, knowing the risk factors and how to reduce them is important for your baby's safety.
Baby Rolling Onto Stomach While Sleeping
Once your baby can roll independently in both directions (back to tummy and tummy to back), you do not need to flip them back over if they roll onto their stomach during sleep. Always place your baby on their back to start sleep, but if they roll on their own, they have the neck and upper body strength to protect their airway. The key is to stop swaddling as soon as rolling begins and ensure nothing else is in the crib. Most babies begin rolling between 4-6 months.
My Baby's Head Shape Looks Abnormal
Many babies develop temporary head shape irregularities that are completely normal. A cone-shaped head from vaginal delivery reshapes within days. Mild positional flattening (plagiocephaly) from sleeping on the back is very common and usually improves with repositioning and tummy time. However, head shape changes involving ridges, a persistently bulging fontanelle, or rapid head growth changes should be evaluated to rule out craniosynostosis.
Achondroplasia (Dwarfism) in Babies
Achondroplasia is the most common form of short-limbed dwarfism, affecting about 1 in 15,000 to 40,000 births. It is caused by a mutation in the FGFR3 gene and is usually apparent at birth with characteristic features including short limbs, a larger head, and a prominent forehead. Intelligence is normal. With monitoring for specific complications and supportive care, children with achondroplasia lead full, active, and independent lives.
Adenoid Hypertrophy and Breathing
Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.