In some countries the number of kids born through c-section are very high, more than half the kids in Brazil are born that way for example, so definitely people can be healthy without getting it from their mothers.

I read it is a practice these days to do this fecal "rub" for newborns as a way to compensate for the C-section lack of it. I do not know if it happens in Brazil. Another factor to consider.

I've never heard of moms doing fecal rubs, but I've heard of many that do vaginal "transplants". I work in a hospital and we get questions quite a bit, moms will often take moist, sterile gauze and conduct the transplant themselves (staff can't really be involved for liability issues).

I just saw it in some documentary, but do not remember where. I found these, which look like what I heard described. I believe it is the same you mention:

https://pmc.ncbi.nlm.nih.gov/articles/PMC11095576/

https://www.nature.com/articles/d41586-024-03449-4

It's not

> can be healthy

Or can they.

It’s (meant to be) an emergency procedure. Benefits: life. Downsides: plenty.

Maybe most relevant in the context of this thread:

“In this systematic review and meta-analysis of 61 studies comprising more than 20 million deliveries, birth by cesarean delivery was significantly associated with autism spectrum disorder and attention-deficit/hyperactivity disorder.“

Zhang, T., Sidorchuk, A., Sevilla-Cermeño, L., Vilaplana-Pérez, A., Chang, Z., Larsson, H., Mataix-Cols, D., Fernández de la Cruz, L., & D’Onofrio, B. M. (2019). Association of cesarean delivery with risk of neurodevelopmental and psychiatric disorders in the offspring: A systematic review and meta-analysis. JAMA Network Open, 2(8), e1910236. https://doi.org/10.1001/jamanetworkopen.2019.10236

A selection of some more:

Keag, O. E., Norman, J. E., & Stock, S. J. (2018). Long-term risks and benefits associated with cesarean delivery for mother, baby, and subsequent pregnancies: Systematic review and meta-analysis. PLOS Medicine, 15(1), e1002494. https://doi.org/10.1371/journal.pmed.1002494

De Mucio, B., Serruya, S., Alemán, A., Castellano, G., & Sosa, C. G. (2019). A systematic review and meta-analysis of cesarean delivery and other uterine surgery as risk factors for placenta accreta. International Journal of Gynecology & Obstetrics, 147(3), 281–291. https://doi.org/10.1002/ijgo.12948

Sandall, J., Tribe, R. M., Avery, L., Mola, G., Visser, G. H. A., Homer, C. S. E., Gibbons, D., Kelly, N. M., Kennedy, H. P., Kidanto, H., Taylor, P., & Temmerman, M. (2018). Short-term and long-term effects of caesarean section on the health of women and children. The Lancet, 392(10155), 1349–1357. https://doi.org/10.1016/S0140-6736(18)31930-5

Li, H.-T., Zhou, Y.-B., & Liu, J.-M. (2013). The impact of cesarean section on offspring overweight and obesity: A systematic review and meta-analysis. International Journal of Obesity, 37(7), 893–899. https://doi.org/10.1038/ijo.2012.195

S., Fleming, J., Bromley, A., Shields, M. D., & Cardwell, C. R. (2008). A meta-analysis of the association between Caesarean section and childhood asthma. Clinical & Experimental Allergy, 38(4), 629–633. https://doi.org/10.1111/j.1365-2222.2007.02780.x

Mascarello, K. C., Horta, B. L., & Silveira, M. F. (2017). Maternal complications and cesarean section without indication: Systematic review and meta-analysis. Revista de Saúde Pública, 51, 105. https://doi.org/10.11606/S1518-8787.2017051000389

Regarding the first study: follow up from the same authors overturns their own results: https://pubmed.ncbi.nlm.nih.gov/33666663/

> Conclusions and relevance: The findings of this study suggest that the association between CD and increased risk of neurodevelopmental disorders in the children was most likely explained by unmeasured familial confounding.