Babies born by caesarean section are more vulnerable to asthma, allergies and infection because they miss out on receiving their mothers' good bacteria during birth.
… This bacteria … [colonises] the intestine …
"This can have long-term health implications, as the development of a good intestinal ecosystem is necessary for health and immunity to allergies, from childhood right through to adulthood."
… emergency caesareans, performed after labour had already begun, meant babies did receive some of the beneficial bacteria, particularly if the waters had broken.
However, elective caesareans … gave babies no chance to pick up any of the good bacteria.
… Australian College of Midwives vice-president Hannah Dahlen said babies born vaginally also had the advantage of hormonal surges during labour that made them more wide-eyed and able to connect with their mothers. Both mother and baby experienced a surge in catecholamines, the fight-or-flight hormone, during labour, making babies more alert at birth.
… white blood cells in babies born by caesarean were different to those of babies born vaginally, potentially altering the way their bodies responded to attacks on their immune systems for the rest of their lives.
The studies could explain dramatic increases in rates of diabetes, testicular cancer, leukaemia and asthma among babies born surgically, said Associate Professor Dahlen.
''In labour, the baby has a gradual escalation in its stress response and then a gradual decline. Research has shown that this could prime our bodies to respond to stress in a certain way,'' she said.
''With a c-section, there is a … dramatic stress response. It could be setting that child up to always over-respond to stress.''