Health & Medicine

The Baby who Demands to Be Breastfed may be Trying to Prevent Future Siblings

Kathleen Lees
First Posted: Apr 23, 2014 10:17 AM EDT

For first-time parents, the night time cries of a newborn can be exhausting, aggravating and above all, libido-killing.

Though many may try and guess why their child just won't seem to stop crying, a recent study suggests that it might not be hunger, a wet diaper or even loneliness. In fact, it might actually be an evolutionary survival strategy that prevents mom and dad from having a new baby.

Lead study author and evolutionary biologist David Haig believes that babies are subconsciously programmed to prevent parents from procreating at night. Besides waking everybody up, frequent nightly feedings can also cause hormonal changes that may disrupt ovulation.

Often times, the study notes that babies begin to cry more at around the 6-month-stage--a time when many parents are getting back in the groove of a normal sex-life. 

The study also shows that certain genetic disorders inherited from the mother or fathers side may play a role in how often the baby cries. For instance, babies with certain genes from their mothers are more likely to sleep longer without disturbances. On the other hand, babies with certain genes from their fathers are more likely to wake up frequently. This makes evolutionary sense, according to Haig, via a press release: "Because fathers have no guarantee that the next baby will also be his, they (men and their genes) are presumably not interested in ovulation starting again."

Though there is no way to test if crying more at night actually helped some survive in early periods of evolutionary history, crying at night as a mean's of survival in modern-day society is no longer necessary.

"I think that it's an adaptation for a world very different from the current world," Haig said, via the release, adding that health care, birth control and good nutrition essentially prevent the need for this survival strategy, today.

However, the question remains: Why did babies evolve to cry more at night?

The matter is still unclear, but Haig answers the message for modern parents: " Babies who don't breastfeed during the night and babies who take bottles don't wake up as much during the night - and they don't seem to be worse off for it. That result implies that nursing throughout the night isn't necessary. So moms shouldn't beat themselves up if they don't always heed the nighttime calls to breastfeed."

More information regarding the findings can be seen via the journal Evolution, Medicine and Public Health

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