Sleeping positions

10% favoured the "lovers' knot" (facing each other with legs intertwined), though all but 2% separated before going to sleep.

[2] In the 1958 edition of his best-selling book The Common Sense Book of Baby and Child Care, paediatrician Dr Benjamin Spock warned against placing a baby on its back, writing, "if [an infant] vomits, he's more likely to choke on the vomitus."

However, later studies have shown that placing a young baby in a face-down prone position increases the risk of sudden infant death syndrome (SIDS).

A 2005 study concluded that "systematic review of preventable risk factors for SIDS from 1970 would have led to earlier recognition of the risks of sleeping on the front and might have prevented over 10,000 infant deaths in the UK and at least 50,000 in Europe, the USA, and Australasia.

"[3] The brain parenchyma rids itself of harmful proteins through the glymphatic system, especially during sleep.