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The human body is home to trillions of microbial organisms – bacteria, viruses, and fungi, collectively known as the “human microbiome.” In the digestive tract, bacterial residents outnumber our own cells by at least 10 to 1. Gut bacteria play a fundamental role in human health by promoting intestinal homeostasis, stimulating development of the immune system, providing protection against pathogens, and contributing to the processing of nutrients and harvesting of energy. The disruption of the gut microbiota has been linked to an increasing number of chronic diseases, yet only recently has infant microbiome health begun to receive research attention, despite the fact that modern birth practices may be upsetting nature's intended balance in significant ways and impacting an important early “window of opportunity,” when microbial colonization has a potentially critical impact on human health and disease.
As a doctor, I appreciate the indispensable, lifesaving contributions of western medicine – such as cesarean sections and antibiotics. They’re examples that, for many women, help avoid the largely preventable tragedy of maternal mortality, which according to the World Health Organization remains unacceptably high in developing countries where access to procedures like cesareans and appropriate pharmaceuticals are too often limited or entirely unavailable.
And now, I do have a “but…” to add here (did you see it coming?), because as lifesaving and indispensable as some medical procedures can be, that doesn't mean they are not overused, and even when done appropriately, can have unintended consequences – sometimes wide-scale, long-term ones.
All animal studies to date associated with symbiotic communities of microorganisms show us that the complex world of our gut microbiome plays an enormous role in human development across multiple body systems – from our skin and gut itself, to our immunologic, metabolic, and cognitive health – even to our stress capacity, resilience, and emotional responses. The foundation development of the gut microbiome is highly influenced by what is referred to as ‘mode of delivery,” in common parlance, how we give birth – in particular, whether vaginally or by cesarean section – and affects our development across all of these parameters – not only immediately, but potentially for a lifetime.
This article (and accompanying podcast episode) is absolutely not meant to challenge, shame, or frighten any individual woman making a personal decision to have a cesarean section as her mode of birth, nor to suggest that having a cesarean (or receiving antibiotics for any reason in labor, for example, for Group B Strep neonatal infection prevention), is all gloom and doom for infant and child microbiome development or always accompanied by long-term health or medical adverse outcomes.
However, it is intended to raise awareness about the need for changes in an obstetric system that has been unequivocally demonstrated to lead to the overuse of interventions in labor, including and perhaps especially cesarean section, through a deeper exploration of the potential consequences. It is also intended to raise awareness of the subtle but significant importance of a healthy gut microbiome in the overall optimal development of multiple and interconnected systems including our skin, immune, metabolic, cognitive, and emotional health
The Paradox of Unintended Consequences
Antibiotic use and cesarean sections are prime examples of practices that, while lifesaving when used appropriately, have both been widely overused in recent decades – and we're facing the consequences now.
The rate of cesarean-section delivery in the United States has increased by 60% since 1996 and now accounts for more than 30% of all births, is increasing globally, and now exceeds 60% in some countries. While sometimes absolutely necessary and indicated, cesareans are also associated with increased maternal infection, hemorrhage, and even death, has led even obstetric societies in the US to seek strategies for reducing what currently sits at a 34% national cesarean section rate. For the record, the World Health Organization (WHO) has stated that cesarean section is likely necessary in 10-15% of births, but recommends no more than 15% of births by cesarean section, for best maternal and neonatal safety and outcomes.
One of the problems with cesareans (despite the very obvious fact that they are major surgery, carrying risk of infection and requiring weeks of recovery) is that babies are delivered abdominally, bypassing the bacteria-rich environment of the maternal birth canal. Whew, you might be thinking, that sounds gross anyway. Actually, though, missing this exit ramp means that baby also misses skin and oral inoculation with important organisms, such as Lactobacillus, Bifidobacterium Prevotella, Bacteroides, and Escherichia/Shigella, which have been identified in vaginal and fecal samples from adult mothers' species. These organisms, and others still being identified, are intimately involved in “training” the innate immune system, leading to healthy immune system development, colonization of the baby’s own gut and skin flora that prevent infection, and a host of related developmental functions. On a very basic level, some of these organisms even allow baby to tolerate ingestion of mother’s milk. In fact, these organisms are sometimes referred to as “milk bacteria.”
So why does this matter?
To date, more than 20 studies have found that the microbiome in cesarean-born babes is different than that of vaginally born infants. These differences may persist to 4 years of age, and even when transient these differences impact microbiome development during early-life critical periods of immune and metabolic programming and may pose lasting health consequences.
Antibiotic resistance is another significant and related issue. Primarily a result of antibiotic overprescribing, the meat industry contributes as well – not just to keep animals infection-free, but to cause more rapid weight gain, due to its metabolism inhibiting effects. Prior to COVID it was considered the largest global public health problem we face, and remains in the top three. What's the connection? Cesarean sections in the United States are accompanied by routine antibiotic administration to mom at the onset of the surgery to prevent infection – women undergoing cesarean section have a 5 to 20 times greater chance of getting an infection from birth compared with women who give birth vaginally. As research has been emerging on the importance of the human microbiome on our health, so too has research emerged on the potentially deleterious impacts of early antibiotic exposure and cesarean section – which go hand-in-hand – on the long-term health of our children, including increased risk of obesity, alterations in the intestinal microbiome, increased risk of allergies, and more.
Babies, Birth, and Their Microbiome
During the vaginal birth process (and even beginning prenatally – a topic for another article) the emerging infant is meant to be exposed, across his/her skin, by organisms found in the mother's vaginal canal as well as perinanal region. Multiple body regions are inoculated with these organisms at birth, and baby also inhales and ingests organisms, simultaneously ‘seeding,' if you will, the mucosal surfaces and digestive system with “pioneer” organisms. These organisms then multiply and adapt to their various locations on and in the newborn's body, partly mimicking the mother's microbiome, and also forming the foundation of the baby's own unique microbial signatures.
The past four decades has brought with them a dramatic rise in cesarean rates which has coincided with increases in childhood chronic immune diseases, including allergies, asthma and autoimmune conditions, and metabolic disorders such as obesity. Cesarean birth is associated with an increased susceptibility to the development of these chronic health conditions. Studies have demonstrated that babies born by cesarean have a greater lifetime risk of chronic inflammatory and immune-system mediated diseases including obesity, Type 1 diabetes, asthma, Crohn's disease, and celiac disease – and it is thought other diseases, including juvenile arthritis and immune deficiencies.
Disruption of the microbiota during maturation by low-dose antibiotic exposure can alter host metabolism and increase the risk of adiposity. Even exposure in early life, leading to transient alterations in the gut microbiota, may be sufficient to induce sustained effects on body composition and may enhance the impact of a standard American high-fat diet on obesity.
Neuroendocrine abnormalities, including cognitive and behavioral disorders, have also been associated with early microbiome perturbations. This is thought to be due to the fact that the microbiome influences the integrity of the blood-brain-barrier (BBB). When the microbiome is disrupted, the BBB integrity is as well, and systemic inflammatory and immunologic components may be able to cross into brain circulation and impact neurologic development, In other words, we've starting to uncover that vaginal birth possesses health advantages that cesareans miss out on, and it has been hypothesized that one cause of these conditions is the difference in exposure to maternal vaginal microorganisms during cesarean birth.
Most of these shifts and potentially resultant conditions seem to evolve from immunologic underpinnings secondary to early microbiome disruption. Ongoing research from preeminent perinatal microbiome researcher, Maria Gloria Dominguez-Bello, PhD, and now many others following in her research footsteps, demonstrates that a the natural transmission and colonization of maternal microbes is impaired by delivery via cesarean section.
“But, Dr. Aviva, what if I don't (didn’t) have a choice but to birth by cesarean?”
Yeah, I hear you. It’s frustrating to hear this information and hard not to blame ourselves, because we live in a culture that blames the mom – as if we don’t do that enough to ourselves! The fact is, though, that sometimes cesareans are necessary. If you did birth by cesarean, out of necessity or not, learning about its effect on your baby's health isn't about judging the type of birth you had, mom judging, or mom shaming. It's about exploring possible solutions and letting go of judgment and guilt to focus on what really matters: how we can support our children's health and that of future generations, while also nurturing our own.
I know this probably sounds scary and, to be honest, slightly depressing, but I actually have some great news to share: researchers and microbiologists such as Dr. Dominguez-Bello, whom I had the pleasure of interviewing for my podcast, are exploring solutions to help increase the health outcomes for mothers and babies through a technique they named Vaginal Seeding, which can be used following a cesarean. I touched on the practice here in my article on Protecting Baby’s Microbiome, and you can listen to the podcast on Natural MD Radio instead, here.
While research into the practice of vaginal seeding is new and in the early stages, it does hold great promise for the future health of our children. Curious about vaginal seeding and whether it is safe and recommended for you and your baby? Whether you're expecting yourself, or are a natural health practitioner wanting to help make recommendations on vaginal seeding for your clients, read on for what you need to know.
What is Vaginal Seeding?
Vaginal seeding, in very simple terms, means swabbing baby with vaginal fluids following a cesarean birth. Prior to birth a sterile gauze is folded and inserted into the vagina and left to ‘incubate' by soaking up beneficial vaginal microbiota for one hour.
Subsequently, at birth, the newborn is swabbed with the gauze, on the lips, mouth, nose, eyelids, and face, and then moving to the rest of the body, swabbing the skin for about fifteen seconds, before proceeding to standard newborn examination.
In a landmark but very small pilot series of seven vaginal-born, seven cesarean-born, and four cesarean-born, conducted by Dominguez-Bello et al., the microbiome of infants in whom vaginal seeding was done post C-section resembled that of vaginally delivered infants, especially in skin and anal samples for 30 days after birth.
The procedure is quite simple, but there are guidelines to follow to avoid potential health risks, which I cover in a minute and importantly, this is not yet recommended as a ‘self-help’ practice at this time.
A subsequent study, also done by Dominguez-Bello and her team, used comparative DNA analysis methods to assess the types, variety, and locations of microorganism colonization after vaginal seeding, and demonstrated that vaginal seeding did result in partial restoration of the baby’s microbiome. However, we still don’t yet know whether this partial restitution of these naturally occurring organisms will have a long-term impact on babies’ health. Larger, long-term studies clinical studies are urgently needed to assess this.
To share just how important maternal colonization of the infant microbiome has been recognized to be, a couple of very small studies have even begun to look at the impact of maternal-newborn fecal transplant as a medical means of reversing early microbiome disruption by restoring gut colonization with the mother's flora – and has been preliminarily shown to be successful. This, however, is definitely not something that should be tried at home under any circumstances.
Is Vaginal Seeding Ready for Primetime?
The concept of vaginal seeding is gaining speed in the press, and many moms wonder: is the practice right for me, and more importantly, is it safe for my baby?
So far, as pointed out by the American College of Obstetricians and Gynecologists (ACOG), and Dominguez-Bello herself, the number, sample size, and duration of studies does not suggest that vaginal seeding is ready for primetime. What's more, the pilot study in question involved only women who were not carriers of group B streptococci, had no signs of bacterial vaginosis (BV), and had a vaginal pH of less than 4.5. In other words, we don't have solid data yet on the possible risks associated with vaginal seeding in the general public.
The question is, then, could the potential benefits of vaginal seeding still outweigh the possible risks despite the early stage of research?
The main concern with vaginal seeding is the spreading of undiagnosed infections in the mother (Group B Strep, chlamydia, gonorrhea, human papilloma virus, group A streptococci, and herpes simplex virus, among others), which could result in (serious!) neonatal infection otherwise avoided through cesarean.
While vaginal seeding is not yet recommended outside of formal research protocols because data is still limited, Dr. Dominguez-Bello does state, in my interview with her here, that the practice of vaginal seeding – with proper testing beforehand for infections in mom and supervision by a qualified birth practitioner such as a CNM, OB, or Family Physician – is likely quite safe and simply exposes baby to what she or he would have been exposed to any had the birth occurred vaginally. That being said, I agree with Dr. Dominguez-Bello and other physicians and scientists who recommend waiting until more evidence is available before commonly practicing vaginal seeding, and all agree that pregnant women should be tested for GBS, HIV, Hepatitis B & C, and VDRL, and should be negative for genital HSV before proceeding with it. Several larger studies are underway now.
The interest in vaginal seeding does reflect a really interesting and promising shift in our collective mindset regarding birth and the importance of the microbiome on children's health. Mothers are waking up to the fact that their children's health is suffering, and that it's time we do something about it. Widespread allergies, food intolerances, eczema, asthma, autoimmune diseases, obesity, diabetes… I've certainly seen the rise in health concerns in children in the last decades, both as a midwife, a herbalist, as a doctor, and as a mom and grandma.
So, until more research is completed and vaginal seeding becomes standard practice, what can we do to support a healthy microbiome right from the start? Here are some of my recommendations below.
Supporting the Newborn Microbiome
Reduce unnecessary cesareans
One of the best ways to support your baby's microbiome right from the start is to avoid unnecessary cesarean. This includes allowing for more time for labor to progress in the active phase, along with working with a midwife and doula, and of course, educating yourself about birth (start here, and here). Listen to my Natural MD Radio podcast episode with Neel Shah, MD, to learn more about unnecessary cesareans and how you can avoid one, and make sure to join The Mama Pathway – not your average childbirth education program!
Breastfeed – at least for the first few months
Numerous studies demonstrate the benefits of breastfeeding. We now recognize breastfeeding as the next phase in the continuum of baby receiving healthy doses of mom's microbiome – transmitted both through the milk itself, with its own microbiota, numerous other immunoglobulins and other factors that support further development of a healthy infant gut, and also via the skin around the nipple which has its own important microbiome that adds to the benefits of breastfeeding. While the WHO recommends an ideal length of 2 years for breastfeeding, even just breastfeeding for those first few months may play a significant role in supporting your baby's microbial, gut, immunologic, and metabolic health.
Practice attachment parenting
Starting at birth with skin-to-skin contact, continuing with breastfeeding ideally through the first year of life with no solids until at least 6 months or baby shows social readiness for food (reaches out for foods you’re eating and wants to put things in her/his mouth), and extending lots of cuddles with skin-to-skin and co-sleeping, encourages transfer of beneficial bacteria to baby and gets us closer to what nature intended.
Consider a probiotic
While not all practitioners agree on the value of using probiotics in infants, preliminary research suggests that giving probiotics to babies born via cesarean could lead to health benefits later in life. While researchers haven't yet confirmed whether boosting a healthy baby's gut with beneficial bacteria could lead to lower incidence of disease, the hope is that supporting diversity of bacteria may help fight conditions like allergies and autoimmune diseases. Probiotics are a perfect example of a process that offers little risk and many possible health benefits, so I encourage moms to both take them during pregnancy and breastfeeding, and give them directly to baby.
Get dirty
As your child is able to sit up and play, encourage your child to “get dirty” in clean, natural outdoor spaces. While we have come to culturally equate ‘dirt’ with ‘unclean,’ we’ve also missed out on important exposures to soil microbiota that also inoculate us and prime a health immune system. Playing outdoors, having pets, and being exposed to natural environments have all been associated with reduced rates of allergies, asthma, and eczema.
Talk with your provider about vaginal seeding – and stay tuned for more research
If vaginal seeding is something you want to try – have a comprehensive discussion with a medical provider you trust and can rely on do help with assess whether this is safe for your baby and your situation. Share not just this podcast episode, but the article because it includes extensive, current references. Make sure to get thorough testing for possible hidden infections, and don't feel pressured to do try vaginal because it's trendy. Again, it's still in early stages of research.
Take care of you!
A healthy mama is at the core of supporting the health of your baby's microbiome, so remember to also restore your own microbiome after a cesarean (or if you’ve had antibiotics in labor for GBS or any other reason) with probiotic-rich foods such as fermented vegetables and yogurt, and give yourself time to recover, allowing for self-care and rest.
Doing Our Best & Forgiving Ourselves
As I talk about in my accompanying article and podcast, Protecting Your Baby’s Microbiome from the Start, we aren't to blame for many factors that have led to the massive overuse of medications and surgeries, and for some time to come, in addition to the necessary and life-saving cesareans that are performed, many women will continue to experience unnecessary surgeries as we slowly make shifts in a system with entrenched misguided practices. And sometimes an antibiotic will be necessary.
The best thing we can do is to be educated, have the tools we need to, whenever possible, identify and avoid unnecessary obstetric interventions, and continue to do what we can – both via research and commonsense practices, to help nature restore what may have been disrupted. And ultimately, forgive ourselves – if you did have a cesarean, take an antibiotic, or give your baby one – first off, it may have been absolutely medically necessary, but even if you're now not so sure it was, you still did it with the best intention for your baby. You're a good mom. As Maya Angelou so famously said, “Do the best you can until you know better. Then when you know better, do better.”
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