「Tummy sleeping gives a rounder head, so it’s fine」

Where the claim comes from

Babies who lie on their backs a lot can indeed develop a flat spot, and tummy sleeping looks like the fix. But it trades a correctable cosmetic issue for a risk that cannot be undone.

What the evidence says

The American Academy of Pediatrics (AAP) safe-sleep guidance is back sleeping for every nap and every night up to 1 year of age. Babies who sleep on their backs are much less likely to die suddenly than those on their stomachs or sides, and the side position is just as dangerous as the stomach. For head shape the AAP points somewhere else entirely: supervised tummy time while awake, which supports motor development and helps prevent flat head syndrome.

What to do instead

• Put your baby down on their back for every sleep, on a firm, flat surface with only a fitted sheet — no pillows, blankets, toys or bumper pads.
• Build up awake tummy time: start with short sessions soon after coming home and work up to at least 15 to 30 minutes a day by 7 weeks, always with an awake adult watching.
• Once your baby is comfortable rolling both ways, you do not need to keep turning them back if they roll over in their sleep; keep the bed free of soft objects.
• Share a room, not a bed, for at least the first 6 months.