SIDS Risk Timeline Calculator
Parents often worry about SIDS - sudden infant death syndrome - especially when putting their baby down to sleep. You’ve heard the warnings: back to sleep, no blankets, no pillows. But how long does this risk actually last? The answer isn’t as simple as a single month or milestone. SIDS risk doesn’t vanish overnight. It drops sharply, but it doesn’t disappear until your baby is well past their first year.
The Peak Risk Window: 2 to 4 Months
The highest risk for SIDS happens between 2 and 4 months of age. About 90% of all SIDS cases occur before 6 months. This isn’t random. Babies in this age range are still developing the brain controls that help them wake up if they’re struggling to breathe. Their airways are small, and their ability to turn their head or push away bedding is limited. That’s why the American Academy of Pediatrics says the safest sleep environment for babies under 6 months is on their back, on a firm, flat surface, with nothing else in the crib.
Even a loose blanket, a stuffed animal, or a bumper pad can increase the risk. These items don’t just add comfort - they can block airflow or cause overheating, both known SIDS risk factors. The risk doesn’t mean your baby will be harmed, but it does mean you need to be extra careful during these months.
Why Blankets Are a Problem - and What to Use Instead
Many parents think a light blanket is harmless. But in reality, any loose fabric in the crib can shift over the baby’s face during sleep. Even a thin cotton blanket can cover the nose and mouth if the baby rolls or moves. The risk isn’t about how heavy the blanket is - it’s about whether it can move independently.
Instead of blankets, use a wearable blanket or sleep sack. These are designed to keep your baby warm without the danger of loose fabric. Look for ones made from breathable cotton or bamboo, with a TOG rating that matches your room temperature. A TOG of 1.0 is perfect for most nurseries. If the room is cooler, layer a onesie underneath. Never add a blanket over the sleep sack.
Studies from the CDC show that using a sleep sack instead of loose bedding reduces SIDS risk by up to 65% in babies under 6 months. That’s not a small difference - it’s life-saving.
When Does the Risk Start to Drop?
After 6 months, the risk begins to decline. Your baby is now stronger, more mobile, and better at controlling their head and body. They can roll over, push up on their arms, and even sit up - all things that help them escape a dangerous position. By 8 months, most babies can turn from their stomach to their back and vice versa, which greatly reduces the chance of suffocation.
Still, the risk doesn’t vanish. About 10% of SIDS cases happen between 6 and 12 months. That means you can’t just relax at 6 months and assume you’re safe. The safest practice is to keep the crib empty - no blankets, pillows, or toys - until your baby is at least 12 months old.
Some parents start introducing blankets around 9 or 10 months because their baby seems ready. But unless your pediatrician says it’s safe, wait. The American Academy of Pediatrics recommends keeping soft objects and loose bedding out of the crib until the baby’s first birthday. That’s not just a suggestion - it’s based on years of data showing that babies who sleep with blankets in their crib are at higher risk, even after 6 months.
What About Co-Sleeping and Bed Sharing?
Bed sharing - sleeping with your baby in your bed - is one of the biggest risk factors for SIDS, especially in the first 6 months. Even if you’re not smoking, drinking, or using drugs, the risk is still higher than sleeping in a separate crib. The reasons are simple: blankets, pillows, and your body can accidentally cover your baby. Babies can also get trapped between the mattress and the wall or headboard.
Room sharing - having your baby sleep in their own crib or bassinet in your room - is strongly recommended. The CDC says this reduces SIDS risk by up to 50%. You’re close enough to comfort your baby, but they’re still in a safe sleep space. Many parents find this easier than they expect. It makes nighttime feedings smoother and helps you notice if your baby is breathing irregularly.
Other Risk Factors You Can Control
SIDS isn’t caused by one thing. It’s the result of several factors coming together. Some you can’t control - like a baby’s brain development. But many you can:
- Don’t smoke during pregnancy or after birth. Babies exposed to smoke are three times more likely to die of SIDS.
- Avoid overheating. Dress your baby in one more layer than you’d wear. If their chest feels hot or sweaty, they’re too warm.
- Use a pacifier at naptime and bedtime. Studies show pacifier use during sleep reduces SIDS risk by about 50%. If your baby refuses it, don’t force it. But if they take it, keep offering it.
- Get prenatal care and keep up with vaccines. Babies who get all their shots on time have a lower SIDS risk.
These aren’t just tips - they’re backed by research from the National Institutes of Health and the CDC. Following them doesn’t guarantee your baby won’t be affected by SIDS, but it cuts the odds dramatically.
When Is It Really Safe to Use a Blanket?
The official answer: wait until your baby turns 12 months old. That’s the age when the risk drops to less than 1% of what it was at 2 months. Even then, don’t rush. Some babies are still small or not fully coordinated at 12 months. If your child can’t stand, climb out of the crib, or roll over reliably, hold off a little longer.
When you do introduce a blanket, choose a thin, lightweight one - no more than 100% cotton, no fluff or fleece. Tuck it in tightly at the foot of the crib, so it only reaches the baby’s chest. Never let it cover their head. And always check before bed to make sure it hasn’t slipped up.
Many parents worry their baby will be cold without a blanket. But babies regulate their body temperature differently than adults. They’re fine with a sleep sack and a onesie. If your baby’s hands are cool, that’s normal. Check their chest or back - if it’s warm and dry, they’re at the right temperature.
What If Your Baby Rolls Onto Their Stomach?
Once your baby can roll over on their own - usually between 4 and 6 months - you don’t need to turn them back onto their back every time. The AAP says it’s safe to let them sleep in whatever position they choose, as long as they started on their back and the crib is still free of loose items.
This is a big shift from older advice. But research shows that babies who can roll over have developed the motor skills to protect themselves. The risk isn’t gone, but it’s much lower. Still, don’t put your baby to sleep on their stomach intentionally. Always start them on their back.
Final Checklist: SIDS Risk Timeline
- 0-2 months: Highest risk. No blankets, no pillows, no toys. Use a fitted sheet and a sleep sack.
- 2-6 months: Peak risk period. Keep crib empty. Room share, don’t bed share.
- 6-12 months: Risk drops, but still present. Still no loose bedding. Continue using a sleep sack.
- 12+ months: Safe to introduce a thin blanket, but still avoid pillows and stuffed animals.
SIDS is rare - about 1 in 1,000 babies in the U.S. each year. But when it happens, it’s devastating. The good news? You have real power to reduce the risk. It’s not about being perfect. It’s about making smart choices, day after day. Stick to the basics: back to sleep, empty crib, no smoke, and a safe sleep sack. Do that, and you’re giving your baby the best chance to grow up healthy and strong.