London - If you’re reading this next to someone who is pregnant, you might want to back off a little.
Expectant mothers need more personal space than the rest of us as they seek to keep a larger "protective bubble" around their bump, a study shows.
While we generally prefer others to stand an arm’s length away from us to feel comfortable, mums-to-be who are near their due date need double that, researchers found.
They say this is because the women have a heightened sense of danger to their unborn baby. But it is also thought their changing body shape and size could make it feel like strangers are closer to them than they actually are.
For the study, scientists assessed women in the second three months of their pregnancy at 20 weeks, in their third trimester at 34 weeks, and at eight weeks after giving birth.
To establish the participants’ personal space, they experienced tapping sensations on their abdomens while two loudspeakers played an approaching "whooshing" noise.
They pressed a button when the ‘tapper’ felt uncomfortable to them. In the case of the 20 weeks’ pregnant women and those who had given birth, there was no significant difference in reaction times to a ‘control’ group of women who were not pregnant.
Their personal space was estimated at around 12 to 16 inches (about 30 to 40cm), roughly an arm’s length away. But that jumped to 26 inches in the group who were in the final three months of pregnancy.
Dr Flavia Cardini, who led the study at Anglia Ruskin University in Cambridge, said: "Personal space is considered a 'safety bubble' and it’s possible that the observed expansion of this at the late stage of pregnancy might be aimed at protecting the vulnerable abdomen during the mother’s daily interactions.
"So, as the mother’s bump grows, in effect the expanded personal space is the brain’s way of ensuring danger is kept at arm’s length."
Dr Cardini, whose research is published in the journal Scientific Reports, added: "Pregnancy involves massive and rapid changes to the body both externally, as the body suddenly changes shape, and internally, while the foetus is growing."
Personal space changes depending on an individual’s relationship to another, so people let family members and friends get closer than they would strangers.
Experts believe it is closely linked to danger, with other studies showing people’s comfort zones become larger when they are played the threatening sound of an approaching barking dog.