Parents overlaying infants – fact or fiction?

Co-sleeping (in the sense of bedsharing) advocates tend to pooh-pooh the idea that overlaying is a realistic hazard while sharing a bed with the baby, especially if you do it “safely”. Here’s James McKenna, the anthropologist who researches the physiological effects of bedsharing (but has, so far, not managed to prove any conclusive SIDS risk reduction as a result), on the subject:

In the worldwide ethnographic record, mothers accidentally suffocating their babies during the night is virtually unheard of, except among western industrialized nations, but here there are in the overwhelming number of cases, explanations of the deaths that require reference to dangerous circumstances and not to the act itself….

…While there is evidence that accidental suffocation can and does occur in bed-sharing situations, in the overwhelming number of cases (sometimes in 100% of them) in which a real overlay by an adult occurs, extremely unsafe sleeping condition or conditions can be identified including situations where adults are not aware that the infant was in the bed, or an adult sleeping partners who are drunk or desensitized by drugs, or indifferent to the presence of the baby.

It’s certainly true that under certain circumstances which constitute unsafe cosleeping – parents under the influence of drugs or alcohol, shared sleep on unsafe surfaces such as waterbeds or sofas – the chance of death from overlaying is far higher than in a safe cosleeping situation. I would also postulate that despite his physiological findings about cosleeping dyads, mothers who are fast asleep may still not be entirely “aware that the infant was in the bed”. But to claim that historically, no infants were ever overlain until the advent of western industrialized nations is complete rubbish.