STUDY: Babies Cry At Night To Stop Mum Getting Pregnant Again

A Harvard researcher is theorising the reason behind night time cries. Image: Shutterstock.

Newborns’ broken night-time sleep patterns are a ploy to stop any siblings being added to the brood, a Harvard researcher says.

A Harvard University Study on infant sleep patterns titled “Troubled Sleep“, published in the Evolution, Medicine and Public Health Oxford Journals, has found night-waking is a survival mechanism for children, a bid to delay their parents getting lucky and producing more offspring.

Researcher David Haig’s theory states that many babies waking in the night to breastfeed are attempting to extend their mothers’ postnatal infertility (lactational amenorrhea) which can sometimes be prolonged by breastfeeding.

Haig said newborns do this to delay the birth of a younger sibling and enhance infant survival — Another baby would mean having to share resources and attention.

He also said breastfed babies tend to increase night-time crying at about the 6 month mark before gradually improving. The study also found night waking is more pronounced in babies that are breastfed.

“Weaned or bottle-fed infants wake less often at night than breast-fed infants and weaning is reported, at least anecdotally, to reduce night waking and alleviate complaints of parents,” the study said.

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