Summary: During the third trimester of pregnancy, a woman’s concept of personal space expands. Researchers believe the alteration in peripersonal space isn’t just connected to alterations in the body map, but also as a mechanism to protect the vulnerable abdomen from injury.
Source: Anglia Ruskin University
New research, published in the journal Scientific Reports, shows that women undergo a significant mental as well as physical change during the late stages of pregnancy.
The study, carried out in Cambridge by scientists from Anglia Ruskin University and the Department of Obstetrics and Gynaecology at Addenbooke’s Hospital, investigated peripersonal space.
This is the area immediately surrounding the body that our brain constantly monitors, as it is where the majority of interactions with the external world occur. It is commonly described as being the area within an arm’s length of another person.
Using an audio-tactile test the scientists measured, for the first time, the boundaries of the peripersonal space during pregnancy.
As well as testing women who were not pregnant, the researchers tested women at the second trimester (approximately the 20th week) when the abdomen is just beginning to enlarge, at the third trimester (approximately the 34th week) when the abdomen is clearly visible, and roughly eight weeks after giving birth.
The study found that a pregnant woman’s sense of personal space expands, but only during the third trimester of pregnancy. No changes were observed at earlier stages of pregnancy or after giving birth, when the size and shape of peripersonal space were both comparable to that of non-pregnant women.
Lead author Dr Flavia Cardini, Senior Lecturer in Psychology at Anglia Ruskin University, said: “Pregnancy involves massive and rapid changes to the body both externally, as the body suddenly changes shape, and internally, while the foetus is growing.
“Our results suggest that when the body undergoes significantly large changes, at the stage when the abdomen is clearly expanded, the maternal brain also begins to make adjustments to the space immediately surrounding the body.
“Peripersonal 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 peripersonal space is the brain’s way of ensuring danger is kept at arm’s length.”
Anglia Ruskin University
Jon Green – Anglia Ruskin University
The image is in the public domain.
Original Research: Open access
“Enlarged representation of peripersonal space in pregnancy”. Flavia Cardini, Natalie Fatemi-Ghomi, Katarzyna Gajewska-Knapik, Victoria Gooch & Jane Elizabeth Aspell.
Scientific Reports. doi:10.1038//s41598-019-45224-w
Enlarged representation of peripersonal space in pregnancy
Our ability to maintain a coherent bodily self despite continuous changes within and outside our body relies on the highly flexible multisensory representation of the body, and of the space surrounding it: the peripersonal space (PPS). The aim of our study was to investigate whether during pregnancy – when extremely rapid changes in body size and shape occur – a likewise rapid plastic reorganization of the neural representation of the PPS occurs. We used an audio-tactile integration task to measure the PPS boundary at different stages of pregnancy. We found that in the second trimester of pregnancy and postpartum women did not show differences in their PPS size as compared to the control group (non-pregnant women). However, in the third trimester the PPS was larger than the controls’ PPS and the shift between representation of near and far space was more gradual. We therefore conclude that during pregnancy the brain adapts to the sudden bodily changes, by expanding the representation of the space around the body. This may represent a mechanism to protect the vulnerable abdomen from injury from surrounding objects.