REPUBLIKA.CO.ID, LONDON -- British doctors say more parents are requesting so-called "vaginal seeding", when a swab from the mother's vagina is wiped into a newborn's mouth after caesarean-section birth, despite a lack of evidence for its medical benefits.

The practice, also known as microbirthing, involves wiping the swab over the baby's mouth, eyes, face and skin to bring it into contact with bacteria from the birth canal.

The hope is this may boost their gut bacteria, and reduce risk of conditions such as allergies or obesity, experts explained in a report in the BMJ British Medical Journal - yet scientific evidence to support it is severely lacking.

"Demand for this process has increased among women attending hospitals in the UK - but this has outstripped professional awareness and guidance," said Aubrey Cunnington, an honorary consultant in paediatric infectious diseases at Imperial College London, who co-wrote the BMJ report.