Smells from pregnant and recently pregnant women may increase men’s interest in their babies, a new study suggests.
The research links the smell given off by new mothers to the length of time male participants want to look at babies’ faces.
“We found preliminary evidence that exposure to post-pregnancy body odours did significantly increase effort expended to view infants’ faces,” the scientists, from Newcastle University and the University of Stirling, said.
For the study a group of 91 men, aged 19-44, were recruited by researchers and told to sniff odour samples repeatedly over a total of 10 minutes.
Some of the odours were collected from five women, aged between 27 and 33 years old, who gave birth during the research period.
The women provided two pairs of odour samples on three separate occasions; during early pregnancy, late pregnancy and after they had given birth.
The men took an online questionnaire both before and after exposure to the smells, which also included those from non-pregnant women.
The male participants were told to press keys to shorten or lengthen the time they wanted to look at images of men, women and babies’ faces.
Scientists found the post-pregnancy odours led to a “marginally significant effect” in the men’s responses to images of baby faces.
Participants who had been exposed to the post-pregnancy smells spent longer looking at the babies than men who were not.
It is possible that the smells given off by pregnant women may make their partners more engaged fathers.
“Our findings can be seen as providing the first evidence that brief exposure to post-pregnancy females’ body odour is sufficient to induce psychological and behavioural changes related to infant care,” the authors of the study said.
“We found that brief exposure to post-partum odours significantly increased the regard value of infant faces.”
The odour samples were collected from the women using cotton pads sewn into t-shirts which participants wore over 24 hours.
Five non-pregnant women, aged 24-29, also provided samples using the same method.
The study’s authors include Caroline Allen from Newcastle University and Craig Roberts, a professor at the University of Stirling.
Their findings are linked to previous studies which show that fathers’ who look after young children experience a drop in testosterone levels.
The team’s research is published in the journal Physiology & Behavior.