Your baby's sleep space matters as much as sleep position. Research indicates the safest setup includes a firm crib or bassinet mattress in your room (but in your baby's own bed) for at least the first 6 months. Keep the crib completely bare—no pillows, blankets, bumpers, or soft toys. These items might seem cozy, but they can block your baby's breathing. A cool room temperature also helps; studies suggest overheating may increase risk. This bare-crib approach takes some getting used to, especially if you're used to decorating nurseries, but the research is clear: simplicity protects your baby.