American researchers are suggesting that natural birth may make mothers more responsive to their babies than those who choose to have a Caesarean.
The researchers at Yale University's Child Study Centre say MRI brain scans on 12 new mothers, taken shortly after birth, found more activity in areas linked to motivation and emotions in those who had a vaginal delivery.
The research team suspect that differences in the hormones generated by birth could be the culprit.
The women in the study had elected to have a Caesarean and the research suggests that contractions, which are an essential part of a natural birth, trigger the release of the hormone oxytocin, which is thought to play a key role in shaping maternal behaviour - oxytocin is a key mediator of maternal behaviour in animals.
Undergoing a Caesarean does not trigger the same release of hormones and the procedure has been linked to an increased risk of post-natal depression.
The Yale team carried out the brain scans two to four weeks after the women had given birth - known as the early postpartum period - and the differences in brain activity were found in regions that not only appeared to influence a mother's response to her child, but also to regulate her mood.
Lead researcher Dr. James Swain says the study might help provide a better understanding of the chemistry underpinning the attachment between a mother and her baby.
The researchers say their results support the theory that variations in delivery conditions such as with Caesarean section, which alters the neurohormonal experiences of childbirth, might decrease the responsiveness of the human maternal brain in the early postpartum.
Obstetricians and gynaecologists say Caesarean births are controversially linked with postpartum depression and it has been recognised for some time that women who undergo the procedure do sometimes have some problems bonding with their baby.
They suggest women who have a Caesarean section should be encouraged to cuddle their newborn against their skin immediately after birth.
They also say as the study selected only women who had elected to have a Caesarean, there might be specific issues which made maternal bonding more difficult for them and women who have a Caesarean were somewhat disengaged from the birth process in comparison to those who go through a natural delivery.