How could vaginal seeding help your c-section baby?

Vaginal seeding: Does it really lead to better health and wellbeing for c-section babies, or is it just a fad?

Many women have heard about vaginal seeding and might be curious as to whether it’s something they should consider. Seeding is a relatively new practice and is undertaken in women whose baby has been born by  Caesarean section. To date, the approach has been to apply the mother’s vaginal fluids to the baby’s mouth, face and body shortly after birth. Why? Good question. OHbaby! asked the experts at the University of Auckland’s Liggins Institute to explain. Here’s what Éadaoin Butler and Professor Wayne Cutfield from the Liggins Institute have to say about this interesting new technique.

In New Zealand about 25% of babies are born by either a planned or emergency C-section each year. C-sections are often life-saving procedures for both mother and baby but, while they’re often performed for perfectly valid reasons, we are beginning to discover that the procedure may be associated with a slightly higher risk of certain health issues for the baby. For example, babies born by C-section have an increased risk of developing conditions such as eczema, asthma, type 1 diabetes and obesity, compared with babies born vaginally. This doesn’t mean all babies born by C-section will develop all, or any, of these conditions, just that they have a slightly greater chance of doing so. But what might be causing this increased risk?

A  ‘BACTERIAL BAPTISM’
Scientists are becoming more aware of the importance of the gut microbiome (the collection of bacteria and other microorganisms living inside us) for health and wellbeing. Our gut bacteria help develop our immune system and aid in our metabolism (affecting our ability to convert food into energy or fat). The womb is a mostly sterile environment, with little to no bacteria present. This means that birth is the first time babies are exposed to a large quantity of bacteria, sometimes referred to as a ‘bacterial baptism’. This ‘baptism’ occurs during a short, but important, period when a newborn’s stomach is not yet acidic, therefore allowing the swallowed bacteria to pass through and colonise the entire length of the gastrointestinal tract. Babies born vaginally naturally encounter their mothers’ vaginal bacteria during birth, and their gut microbiome appears similar to that of their mothers’. However, those born by C-section don’t have this initial contact. Studies have shown that these babies develop a microbiome that is different to vaginally-born babies; it is dominated by bacteria more commonly found on the skin and in the hospital environment. This disrupted initial contact may partly explain the increased risk of future health conditions seen for Caesarean-born babies.

VAGINAL SEEDING
‘Great’, you may say, but this information is of little use to a mum needing a C-section to ensure her little one arrives safely into the world. So, what if there was a way for us to restore that initial missed contact with vaginal bacteria? This is what vaginal seeding is intended to do. It’s the practice of artificially ‘seeding’ a baby with their mother’s vaginal bacteria after they are born. It arose off the back of a US study by Maria Dominguez-Bello and her team¹, published in Nature Medicine in 2016. The researchers wiped the mouth, face and body of Caesarean-born babies with their mothers’ vaginal fluids shortly after birth. At one month of age, the microbiome of those Caesarean-born babies who’d been wiped with vaginal fluids appeared more similar to the microbiome of vaginally-born babies than Caesarean-born babies who had not been wiped. Sounds ideal, right? I mean, why don’t we just go ahead and ‘seed’ all babies born by C-section? Well, there are more details you should know about that study. Firstly, it was a pilot study, meaning it was designed to test the feasibility of the research, rather than determine if seeding actually works. So while some differences were seen at one month, they did not study a large enough number of babies to know that this was because of the seeding. Which leads on to the next point, the number of babies ‘seeded’ was just four. I don’t know about you, but I like my medical procedures to be tested on more than four people before being universally rolled out! And lastly, the researchers didn’t look at the babies’ gut microbiome – only the microbiome in the places where the babies were ‘seeded’ (their skin, anal area and mouth). So, while there was a difference in the microbiome of these areas at one month, there’s no way of telling if the swabbing had any impact on their gut microbiome (the area most associated with health benefits). Considering this promising, but limited, information, it is clear that more research is needed before vaginal seeding of babies born by C-section could become a routine practice.

IS IT SAFE?
A particular concern for many obstetricians is a type of bacteria called Group B Streptococcus (GBS), which can cause serious infection in newborns. In fact, concern around GBS transmission is one of the primary reasons that the American College of Obstetricians and Gynaecologists does not recommend vaginal seeding to be performed outside of a research study². The Royal Australian and New Zealand College of Obstetricians and Gynaecologists has not yet released any specific recommendations regarding vaginal seeding, but they have put a link on their website to a British Medical Journal article about vaginal seeding³. The article encourages clinicians to ensure that their patients are fully informed about potential risks of seeding. To date, we’re only aware of one reported case of likely infection transmission following vaginal seeding, and this was for herpes⁴. This is a serious infection for a baby, and it appears that the baby’s mother was not appropriately screened.

TO SEED OR NOT TO SEED?
Due to current lack of evidence of benefit, and the potential for transmission of infections (if comprehensive screening is not performed), we do not yet recommend that vaginal seeding occurs outside of a research study.  Although this is not a recommended procedure outside of research projects at present, if mothers are going to proceed they need to ensure their obstetrician has arranged comprehensive screening for infections that could be passed on to the baby. It’s still very early days and we don’t really know if it can help babies or not. However, it is important to note that birth is just one of the factors involved in the development of a baby’s microbiome; breastfeeding is a really important piece of the puzzle, and skin-to-skin contact is helpful too. So if your baby can’t be ‘seeded’, you can still help them be colonised with beneficial bacteria.

1. Dominguez-Bello MG, De Jesus-Laboy KM, Shen N, et al. Partial restoration of the microbiota of Caesarean-born infants via vaginal microbial transfer. Nat Med. 2016;22(3):250-253.  2. The American College of Obstetricians and Gynecologists. Committee opinion no. 725: Vaginal seeding. Obstet Gynecol. 2017;130(5):e274-e278.  3. Cunnington AJ, Sim K, Deierl A, Kroll JS, Brannigan E, Darby J. “Vaginal seeding” of infants born by Caesarean section. BMJ. 2016;352:i227.  4. Huynh J, Palasanthiran P, McMullan B. Potential Transmission of Herpes Simplex Virus Via Vaginal Seeding. Pediatr Infect Dis J. 2018;37(11):e278.