Vaginal Seeding after a Caesarean Birth: Safe? Effective? What does the EVIDENCE say?

caesarean birth Vaginal Seeding after a caesarean birth – what’s it all about?

The news this week has been all about vaginas – specifically the idea of “seeding” a newborn’s gut with a swab from the vagina after a caesarean birth.

Vaginal Seeding after a caesarean birth was first widely covered in the film “Microbirth” which covered the work by Maria Dominguez-Bello and her colleagues, looking at whether the differences in gut bacteria between vaginally and caesarean born babies was due to the fact that caesarean born babies do not absorb gut flora from their mother’s vagina. Because these differences are linked to long term health problems, the research is attempting to find whether the swabs help to change the gut bacteria in a positive way.

The results of the pilot study were very positive, with the gut bacteria of 100% of the “seeded” caesarean-born babies being very similar to those of the vaginally born babies, in contrast to the caesarean-born babies who were not seeded where 100% of them had a different microbiome. The authors state that they don’t yet know whether this would impact the baby’s health over time, nor whether the results would replicate with a wider study group, and more work needs to be done.

Concerns have been raised about the risk of infection from vaginal seeding, and the original paper which triggered the media storm recommends not doing vaginal seeding following a birth which was planned as a caesarean specifically in order to reduce the risk of infection from, say, HIV or herpes.  Surely this is self evident? There is also a question of whether pathogens such as Group B Strep (GBS) may put babies at risk – but as many as 1/3 of women carry GBS at the time of a vaginal birth, and there is no reason to think that this would be more readily passed on through seeding than a vaginal birth although this would be important to look at in future studies.

It has also been suggested that amniotic fluid may “wash” the vagina and change the flora experienced by babies passing through during birth compared with seeding the baby after a caesarean birth. The authors of the pilot found that there was no difference in a woman’s vaginal flora before and after birth, so this does not seem to be the case, and most babies do not simply flow down on a wave of fluid!

Perhaps one consideration is that babies are often born with their eyes and mouths closed, and so when considering vaginal swabbing, it would be useful to know whether the swab should be put into the baby’s mouth or eyes, or simply wiped over them. Timing of when is best to use the swab needs to be better understood, and the pilot study says that parents should be aware that skin to skin and breastfeeding are well understood to be extremely important to a baby’s gut health and long term health.

The pilot was very small, with only 18 babies in the study, and the authors are clear that more research is needed. This is contrary to much of the misleading media coverage which has stated that there is no evidence for vaginal seeding after a caesarean birth. There is, it’s just a very small sample study and is not sufficient to change recommendations.

If only medicine was always this diligent.

Guest post by Emma Ashworth