Sudden Infant Death Syndrome (SIDS)

Written & reviewed by the BestDoctors.sg editorial team · Last updated 2 Sep 2026 · General information, not medical advice

Few worries weigh on new parents as heavily as SIDS. It can feel frightening precisely because it is unexpected and unexplained. Yet decades of careful research have taught us a great deal about how to lower the risk, and most of it comes down to how and where a baby sleeps. This guide explains what SIDS is, what raises the risk, and the positive, practical steps that make sleep safer, written in plain terms for families in Singapore.

What SIDS is

SIDS is the sudden and unexpected death of a baby who seemed well, usually during sleep, where a thorough investigation, including review of the medical history and the circumstances, finds no explanation. It is sometimes grouped under the broader term “sudden unexpected death in infancy”. Because no cause is found, it is a diagnosis reached only after other possibilities have been excluded.

It is important to hold two things together. SIDS is genuinely rare, and it has become rarer as safe-sleep advice has spread. At the same time, the risk is not random: it is strongly influenced by the sleep environment, which means families have real power to reduce it. This is not about doing everything perfectly, and it is never about blame. It is about stacking a few sensible habits in your favour.

Who and when

SIDS is most likely during the early part of a baby’s life, in the first months, and becomes much less likely as a baby grows older and stronger. It can happen to families of any background. Knowing this window helps parents focus their attention on safe sleep during the period when it matters most, without carrying that worry indefinitely.

What increases the risk

Several factors are linked to a higher risk. Understanding them is simply a way to know which habits to build:

• Placing a baby on their tummy or side to sleep, rather than on their back.
• Soft bedding around the baby, including pillows, cot bumpers, quilts, soft toys and soft or sagging mattresses.
• Overheating, from too many layers, heavy bedding or a room that is too warm.
• Bed-sharing, especially when combined with other risks such as a parent who smokes, has drunk alcohol or taken medication or drugs that cause drowsiness, or when the baby was premature or small.
• Exposure to cigarette smoke, both during pregnancy and in the home after birth.
• Being born premature or with a low birth weight.

Most of these can be changed, which is exactly why the risk can be reduced so effectively.

Safe sleep: the practical heart of this guide

These are clear, positive steps you can follow for every sleep, day and night:

• Back to sleep, every time. Always place your baby on their back for sleep, for naps as well as at night. This single step is the most protective of all.
• A firm, flat, separate surface. Use a proper cot with a firm, flat mattress, placed in the parents’ room. Sharing a room, but not a bed, is a safe and comforting arrangement in the early months.
• Keep the cot clear. No pillows, soft toys, loose blankets, quilts or cot bumpers. A baby sleeping in a well-fitting sleep bag or lightly tucked-in blanket, with the cot otherwise bare, is safest.
• Not too hot. Dress your baby in light layers suited to the room, and keep the room at a comfortable temperature. In Singapore’s climate this often means fewer layers rather than more. Check the chest or back of the neck; a baby who feels sweaty or hot to the touch is overdressed.
• A smoke-free environment. Keep your baby away from cigarette smoke entirely, and keep the home and car smoke-free.
• Feeding and immunisations help. Breastfeeding, where possible, is protective, and keeping your baby up to date with the recommended immunisations is linked to lower risk as well as protecting against serious infections.

Two cautions are worth spelling out. Never settle to sleep with your baby on a sofa or armchair, as this is a particularly dangerous place for a baby to sleep. And avoid bed-sharing if you or your partner smoke, have drunk alcohol or taken sedating medication, or if your baby was born premature or small, as the risk is much higher in these situations. If you find yourself getting drowsy while feeding, it is far safer to feed in bed than on a sofa, and to place your baby back in their own cot afterwards.

What SIDS is NOT

Some fears deserve to be laid to rest. SIDS is not caused by vaccines; immunisation is if anything associated with lower risk. It is not caused by choking or vomiting in a baby who is sleeping safely on their back; healthy babies have reflexes that clear their airway, and back-sleeping does not increase choking. And SIDS is not the parents’ fault. Families who have followed every piece of advice have still, very rarely, been affected, which is why compassion, not blame, must guide how we talk about it.

Support after a loss

The death of a baby is a profound loss, and grief has no timetable. Parents, grandparents and siblings may all be affected, and reactions such as shock, guilt, anger and deep sadness are all part of grieving. You do not have to carry this alone. Hospital teams at KKH and NUH, your GP or polyclinic, medical social workers, and bereavement and counselling services can offer support, and speaking with others who have experienced a similar loss can help. Reaching out for help is a sign of strength, and support remains available for as long as you need it.

When to see a doctor

Safe sleep is about prevention; separate from that, trust your instincts if your baby seems unwell. See a doctor promptly, at your GP, polyclinic or a children’s hospital, if your baby has a fever, is feeding poorly, is breathing with difficulty, or is unusually sleepy, floppy or hard to rouse. You know your baby best, and it is always right to seek advice when something feels wrong. For an unresponsive baby, or one who is not breathing normally, call 995 immediately and begin infant CPR.

Common questions

Isn’t a baby on their back more likely to choke?

No. This is one of the most common worries and the reassurance is clear: healthy babies sleeping on their backs are well able to protect their airway, and back-sleeping does not raise the risk of choking. It is the safest position.

What if my baby rolls onto their tummy during sleep?

Always place your baby down on their back. Once a baby can roll both ways on their own and confidently, you do not need to keep turning them back through the night, though the cot should still be clear of soft items.

Does a dummy or pacifier help?

Offering a dummy at sleep time is linked with lower risk for some babies. If you use one, it is best not to force it, and if you are breastfeeding many parents wait until feeding is well established. Do not attach it to strings or cords in the cot.

Is it safe to share a room with my baby?

Yes, and it is encouraged in the early months. Room-sharing, with your baby in their own cot beside your bed, is both safe and practical for night feeds. It is bed-sharing under risky circumstances, not room-sharing, that raises concern.

Can I still cuddle and hold my baby to sleep?

Absolutely. Closeness, cuddling and feeding are wonderful and important. The key is simply to place your baby back in their own clear, flat cot, on their back, once they are ready to be put down, and never to fall asleep together on a sofa or armchair.

Related guides

• Newborn jaundice
• Colic in babies
• Reflux in babies
• Childhood vaccination schedule
• Secondhand Smoke (Passive Smoking)

Sources

KK Women’s and Children’s Hospital; HealthHub; The Lullaby Trust; NHS.