C-section babies were swabbed with their mother's bacteria

That missed exposure has been linked to a higher risk of immune and metabolic problems later in life. Researchers at New York University tested whether simply wiping a newborn with gauze soaked in the mother's vaginal fluid could restore some of what the birth canal would have provided.

In a pilot study, four infants delivered by cesarean were swabbed with their mother's vaginal fluid shortly after birth. Over the next month, their gut, mouth, and skin bacteria grew enriched with vaginal bacteria largely absent in unexposed cesarean-born infants, moving closer to the pattern seen in vaginally delivered babies.

The procedure did not fully recreate a vaginal birth's microbial exposure, and whether it changes a child's long-term risk of asthma, allergy, or obesity is still unknown, since the pilot was not designed or sized to answer that question. Larger, randomized follow-up studies were needed before the practice, sometimes called vaginal seeding, could be recommended.

A birth canal, approximated with a swab.