Vaginal seeding – more data required?

A review article written by Danish doctors and published in the British Journal of Obstetrics and Gynaecology has stated that the benefits of vaginal seeding “do not outweigh the risks”. This paper and the inevitable news stories which have been spun from it are causing concern amongst those who feel that vaginal seeding is a positive means of counteracting one of the disbenefits of caesarean section. But the practice of vaginal seeding itself is causing just as much concern amongst others, who say that we don’t know that it is safe.

Vaginal seeding, for the uninitiated, is the practice of exposing caesarean-born babies to their mother’s microbiome (which they would have been exposed to during birth if born vaginally) by wiping their skin with a cloth or swab that has been held near their mother’s vagina.

The alleged safety concerns attributed to the BJOG report need some analysis, however. Only one published study was included in the review, and this study only included four babies. It is impossible with such tiny numbers to draw any conclusions about the potential benefits or harms of any intervention. For now, as I have said before, we can only speculate. One of the useful things that this study highlights is how difficult it can be to determine with confidence which bacteria are healthy and which are always, sometimes or occasionally harmful. We also think that many bacteria are ‘commensal’, which means that they neither harm nor help their human hosts, but our knowledge in this area is in its infancy and we would so often be far wiser to simply say that we do not know.

If we are going to target ways of helping babies acquire beneficial bacteria, then tackling the current overuse of antibiotics has to be a key issue.

Which is, in a way, what the authors of this report are saying. They call for more research, saying that we do not have evidence to support intervening in this way, and list other things that we know can have a positive effect in this area. These things include avoiding caesarean section where not absolutely necessary, immediate skin-to-skin cuddling between mother and baby, breastfeeding for at least 6 months and other factors such as good nutrition during pregnancy. The fact that the authors of this paper cite a lack of evidence as a reason to not recommend vaginal seeding is somewhat ironic, as many of the practices that are used in maternity care are not based on good evidence. Let’s also not forget the vast quantities of antibiotics that are given to women and babies, often on a routine basis rather than in response to a particular concern. If we are going to target ways of helping babies acquire beneficial bacteria, then tackling the current overuse of antibiotics has to be a key issue.

The question of whether vaginal seeding is beneficial and/or risk-laden isn’t a straightforward one. Neither the proponents nor the detractors of this intervention currently have good evidence on which to base their claims – or fears – and the information that women and families receive tends to be based on the beliefs of those who are talking about it. It’s tedious to always read the conclusion that more research is required, but in this case it really is the only thing that is going to help us move to a place where we truly know whether or not vaginal seeding is beneficial.

I talk a lot more about issues relating to bacteria in my online course, Group B Strep Explored – I’d love to help you learn more!

Thor Haahr et al. Vaginal seeding or vaginal microbial transfer from mother to the caesarean born neonate: a comment regarding clinical management. BJOG 2017: DOI: 10.1111/1471-0528.14792
photo credit: Mwesigwa Zoe’s Delivery via photopin (license)

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