Eight years ago, I had an emergency C-section. After four failed attempts to induce labour, I was whisked into an operating theatre for a surgical birth. I am very grateful for the care I received during my daughter’s birth, and believe the doctors and midwives did what they thought was best for my child and me. But having spent the past three years interviewing world-leading scientists for our award-winning documentary Microbirth and our book The Microbiome Effect, I believe some of the decisions made that day may have altered the founding of my child’s bacterial ecosystem, which could have consequences for my daughter’s lifelong health.

Two amazing things happen with a C-section: there’s the main event, the incredible moment when an infant is pulled from a mother’s womb into the outside world. This event is usually an emotional, extraordinary, memorable moment for any mother.

But there’s another amazing event happening simultaneously. This other event, invisible to the naked eye, could impact the baby’s immune and metabolic systems. It could have repercussions for neuro-development. And it has the potential to affect the baby’s lifelong health. This other event concerns the founding of the baby’s microbiome.

 

The human microbiome is the community of trillions of microbes that live on and in us, including bacteria, fungi, viruses, archaea and protozoa. This community keeps the body functioning and helps protect against disease. The microbiome is a hot topic of scientific interest right now and a particularly rich area of research concerns the narrow window that surrounds childbirth.

Scientists have discovered that during pregnancy, the mother’s microbiome changes in preparation for the transfer of microbes from mother to baby which occurs during vaginal childbirth. This main “seeding” of the infant microbiome is an intricate, exquisite process. While in the womb, the baby develops in a near-sterile environment protected by an amniotic sac. The infant might receive some prenatal exposure to small colonies of microbes from the mother’s womb, amniotic sac and placenta – but the main founding of the infant microbiome begins when the amniotic sac is ruptured. As soon as the waters break, the infant is flooded with a wave of microbes.

With vaginal birth, this deluge usually happens whilst the baby is in the birth canal. A special microbial payload of bacteria from the mother’s vagina washes over the baby, coating the baby’s skin and entering the nose, ears, eyes and mouth. Meanwhile, as the baby emerges into the outside world, he/she is likely to come into contact with the mother’s faecal matter; scientists believe this could be a good thing as it exposes the baby to the mother’s intestinal microbes.

More microbes are received from immediate skin-to-skin contact with the mother, from breastfeeding, from the air, and from being touched or kissed. Some swallowed bacteria reach the infant’s intestines to found the baby’s gut microbiome. The first microbes to arrive in the gut help train the infant immune system and because of a gut-brain axis, scientists believe that infant gut microbes could also play a key part in neuro-development.

With C-section, it’s a slightly different process. As the baby doesn’t pass through the birth canal, it isn’t exposed to the mother’s special payload of vaginal microbes (unless the amniotic sac has ruptured prior to the C-section being performed). In addition, the infant won’t usually come into contact with the mother’s faecal matter during surgery so is unlikely to be exposed to the mother’s intestinal microbes.

 

Instead, if the waters are still intact when the C-section surgery begins, the infant’s first main exposure to microbes occurs when the surgeon slices open the amniotic sac whilst the baby is still inside the womb. As soon as the amniotic membranes are split open, the baby becomes deluged with microbes. Assistant Professor Maria Gloris Dominguez Bello from New York University, one of the key scientists featured in our film and book, found that with C-section babies, those first microbes come from the air and are likely to originate from the skin of someone in the operating theatre. As with vaginal birth, more microbes are then acquired every time the baby takes a breath, is touched, handled or kissed.

With regards to my own C-section, my amniotic sac was still intact when the surgery began so my daughter would not have received any exposure at all to my vaginal microbes. As far as I know, there was no contact with my faecal matter, so no exposure to my intestinal microbes. Therefore, my daughter’s main first microbial exposure is likely to have been from the air of the operating theatre. My daughter needed resuscitating when she was born and was worked on by a neonatal team, so this physical contact would have transferred more microbes.

 

When I struggled to breastfeed immediately after the birth, a nurse urged me to give formula milk “for the sake of the baby”. My daughter might have received some nutrition from the formula milk, but would have missed out on many of the essential components of colustrum (the first breast-milk produced), including immune cells, antibodies, growth factors, many additional species of microbes and and special sugars called oligosaccharides. These special sugars in breast milk are prebiotic, which means they are indigestible by the baby, but they can be digested by the microbes newly arrived in the baby’s gut. These special sugars encourage good bacteria to thrive and quickly colonise the baby’s gut, therefore crowding out harmful pathogens.

If a baby is born by C-section and is formula-fed, they have an “altered” gut microbiome in early life – this means their microbial profile is different from what it would have been like if the child had been vaginally born and exclusively breastfed. As the first gut microbes to arrive help train the infant immune system, an “altered” gut microbiome might mean that the immune system is not optimally trained, with potentially lifelong consequences. The science is emerging and there’s no definite conclusive proof yet, but an “altered” microbiome is one hypothesis to explain why babies born by C-section are at an increased risk of developing immune-related conditions including asthma, coeliac disease and juvenile diabetes. C-section babies are also at increased risk of becoming overweight or obese later in life.

Looking back now, many of the things done by doctors, midwives and nurses around the time of our daughter’s birth, and done with the very best intentions and with our full consent as parents, were probably done at the expense of our daughter’s microbes. There’s no blame. The doctors didn’t know about the microbiome back then. As parents, we didn’t know.

 

Given the benefit of hindsight, if I would have known then what I know now, I would have asked for things to be done differently. During pregnancy, I would have had my vaginal microbiome tested to make sure that my vaginal microbiome was free from any potentially harmful pathogens.

If I still needed a C-section, and if my vaginal microbiome had tested negative for pathogens, I would have “swab-seeded” my baby’s microbiome. “Swab-seeding” (or “Microbirthing” as it has sometimes been called after our ‘Microbirth’ film) is a technique currently being researched by Dr Maria Gloria Dominguez Bello at New York University. The technique involves wiping the mouth, face and body of a newly born C-section infant with a swab taken from the mother’s vagina, thereby partially restoring some of the microbes the infant would have received if born vaginally.

If possible, I would have wanted a woman-centred C-section; for an intravenous line to be inserted into my non-dominant arm, for the screen to be lowered so that I could see the actual moment of birth, for my baby to be delivered straight onto my chest to allow for immediate skin-to-skin contact (unless she needed emergency treatment) and to be fully supported with exclusive breast-feeding.

 

A critical aspect of the microbial transfer during vaginal birth is transgenerational. In other words, a mother passes on her own unique set of microbes to her child. This means the infant microbiome resembles the mother’s, the grandmother’s, the great-grandmother’s, and so on, if they all had vaginal births. In this way, vaginal birth can be viewed as a kind of chain of maternal heritage – microbes are passed from one generation to the next, and any protection from disease provided by a mother’s diverse microbiome could also be passed on to her child.

With C-section, the chain of maternal heritage is broken. A mother’s microbiome is not passed on to her baby. Therefore a C-section baby has a completely different microbial profile to its mother, grandmother, great-grandmother and so on.

You can only do what you think is best with the knowledge available at the time. Am I grateful that my daughter was born safely by C-section? Obviously, yes. But does it jar with me that the chain of maternal heritage was broken? Yes. Am I worried that she had an “altered” gut microbiome at birth which could mean she’s at higher risk of developing one or more immune-related conditions later in life? Yes, but it’s within my power to make sure she eats a diverse microbe-friendly diet and that she enjoys a microbe-friendly lifestyle (the subject of our next film).

 

I am not trying to make any mother feel guilty about the circumstances of her birth. I simply want to raise awareness that vaginal birth where possible, immediate skin-to-skin contact plus exclusive breastfeeding could give the best possible start for the infant microbiome. C-sections are not going to go away. They are an important often life-saving procedure. If a C-section does become necessary, then the “swab-seeding” technique could possibly provide a solution in the future to partially restore an “altered” infant microbiome (provided Dr Maria Gloria Dominguez Bello’s strict inclusion criteria is followed and that mothers test negative for harmful pathogens).

I just wish I’d known then how considering the impact of infant microbiome could bring lifelong health benefits. It could be best for the child’s long-term health, and potentially, even best for the health of future generations.

Toni Harman is the co-author of the book The Microbirth Effect, published by Pinter and Martin, and co-director of MIicrobirth, an award-winning film produced by Alto Films Ltd