My mother’s generation, who gave birth during the 1950’s and 1960’s, had a less-stressful, less-worrisome time of it than those of us giving birth in the 21st century. A parenting book in the 1950’s actually advises expectant mothers to limit themselves to only two highball cocktails a night! Whereas we are given strict prohibitions on a wide variety things – alcohol, soft cheese, sushi, hot-tubs and so on and so on!
We are becoming parents during an era where science has learned more about how choices a mother makes can affect her unborn child. It’s also a time where dramatic headlines attract internet clicks and scare tactics sell books and magazines –a “culture of fear.” The well-known pregnancy book, What to Expect When you are Expecting, is extremely informative about pregnancy and fetal development. Nevertheless, I put that book permanently aside after it scared me to death with an extensive list of all the things I could do to screw up my unborn child. Lots of pregnancy products prey on a mother’s fear and guilt.
However there can be truth behind some of the scary sound bites – so figuring out what is worth worrying about and what is merely fear-mongering becomes important. As future parents, we want to take all reasonable steps to give our babies the best chance in the world, such as taking pre-natal vitamins, stopping alcohol consumption and cigarette use and eating healthily. We might also try to limit our exposure to toxic chemicals like insecticides and pesticides. But how much more do we realistically need to do to ensure our unborn children get the best possible start in life?
There is a documentary film that has received a lot of press among the healthy-living crowd called, “Microbirth.” This film introduces the concept of planning a birth to promote establishment of a healthy microbiome in a newborn baby. The film draws a link between the method by which a baby is born and the types of microbes that they are first exposed, which later make up the baby’s microbiome (healthy microbes including yeasts and bacteria that live in the digestive tract and provide benefits to their host). The film claims that there is a connection between the initial microbial exposure to health problems that may arise later in life. The filmmakers state:
The purpose … is to raise public awareness of the importance of “seeding the baby’s microbiome” at birth with the mother’s own bacteria – this bacteria helps train the immune system to recognize what is “friend” and what is “foe”. We believe “seeding of the baby’s microbiome” should be on every birth plan – for even if vaginal birth isn’t possible, immediate skin-to-skin contact and breastfeeding can still help to provide bacteria crucial to the development of the baby’s immune system.
In addition to everything else there is to think about, do new parents really need to also worry about seeding their baby’s microbiome with mother’s microbes during the birth process?
Link Between Gut Microbiome, the Immune System and Brain
Friendly microbes living in our digestive tract (commensal bacteria) support our immune system in vital ways. Some of the commensal bacteria, when exposed to immune cells in the human body, trigger the immune cells to start dividing and multiplying, ensuring that there are sufficient numbers to ward off threats. These immune cells then produce antibodies to fight disease-causing microbes so having more of them means they are better at warding off attackers.
Our commensal microbes perform a vital role in training the immune system to identify harmful microbes and to ignore harmless microbes and particles which come into the body. They also trigger the immune system to respond to threat. Allergies are the result when an immune response is triggered unnecessarily by what are actually harmless substances that are wrongly perceived as being a threat (allergens).
Additionally, some of our commensal microbes help to train the immature immune system to identify between what is self and what is non-self. When the immune system cannot do this effectively, auto-immune disorders, where the body attacks parts of itself causing chronic inflammation, can be the unfortunate outcome.
f the immune system is effective at identifying and responding to threats, good health is the happy result. However, if the immune system fails to identify or dispatch harmful microbes or toxins, illness follows. Having the immune system get it right makes a big difference for our well-being.
Scientists have observed in mouse experiments, where the mice were raised in a sterile environment to be germ-free, that the immune system developed poorly in the rodents lacking beneficial microbes.
Researchers at UCSF and the Henry Ford Health System in Detroit have observed that a particular pattern of microbes living in a human baby’s gut during its first month of life seems to directly impact the developing immune system, leading to a higher risk of allergies and asthma later in childhood.
There is even some speculation within the medical community that an unhealthy gut microbiome can affect the development of the brain in a child. Some experts believe that Autism, ADHD/ADD, learning disabilities (for example dyslexia), mood disorders (such as depression, anxiety and bipolar disorder) and even Schizophrenia are linked to an unhealthy mix of gut bacteria.
Since having health-promoting microbes living in the gut is a vital component of an effective immune system and may promote healthy brain development, making sure the right commensal bacteria colonize our children is a very worthy goal.
How do Microbes Colonize a Newborn Infant?
Since we now understand how important it is for an infant to develop a healthy microbiome, it is important to understand how colonization first occurs in the early part of life.
For a long time, doctors believed that babies were microbe-free in the womb and that the womb was a sterile place for baby to develop. Recently, however, we have started to learn that babies get their first exposure to bacteria from swallowing amniotic fluid from the mother while still in utero. This swallowing and the placenta which delivers small amounts of commensal bacteria together provides the babies first contact with the microbial world. All together, however, the amount of microbe transfer in utero is small as babies are born with relatively uncolonized digestive tracts.
During a vaginal birth, a baby is literally bathed in the microbes that inhabit his mother’s birth canal and he swallows many of them in the process. For babies born via their mother’s birth canal, this is the largest exposure to healthy commensal bacteria that the infant receives in early life. The microbes in the vaginal microbiome make their way to the digestive tract and where they are the primary colonizers of the baby’s gut microbiome. Many of these early colonizers play a critical role in developing and supporting the infant’s immature immune system.
Over the course of a woman’s pregnancy, the mix of microbes in her vagina (vaginal microbiome) actually evolves and changes to increase numbers of bacteria that are beneficial to her infant. For example, Lactobacillus johnsonii, which is normally found only in the gut, increases in percentage in the vagina over the course of a pregnancy. Interestingly, L. johnsonii are known to assist in the digestion of milk, which is a baby’s primary food source for many months.
Breastfeeding and Skin Contact
Mother’s milk is rich with beneficial microbes. There is a wide diversity of healthy microbial species within the milk itself. Researchers have determined that many of the microbes typically found in the mother’s digestive tract make their way into her milk, aiding in the colonization of her baby’s gut microbiome, where they assist in digestion and in bolstering the immune system of the baby.
Additionally, if the baby is breast fed, the mouth to skin contact between the nursing infant and the mother’s breast transfers bacteria from the mother’s skin to the infant’s gut.
Therefore, the mix of microbes that eventually colonize a baby’s digestive tract may be of a different composition depending on what and how they are first fed following birth.
Disruptions to Transfer of Health Promoting Microbes from Mother to Child
There are two significant factors that can inhibit the usual transfer of health promoting microbes from a mother to her newborn baby: antibiotics and cesarean section (C. section). This is ironic because both of these treatments are designed to promote health and in fact do save lives. It is the unnecessary use of both, however, that poses a health concern. Using them sparingly, and only when indicated can prevent unnecessary disruptions to the colonization and development of a baby’s digestive tract by health-promoting, commensal microbes.
When administered to stop a dangerous bacterial infection, antibiotics can be lifesaving, but this benefit is not without cost. They are meant to kill disease-causing bacteria, but antibiotics do not distinguish between good, commensal bacteria and bad, pathogenic bacteria. They kill bacteria indiscriminately.
Doctors are reluctant to prescribe antibiotics to pregnant women, but will do so when the mother or the fetus is dangerously ill. In this situation, prescribing them is the best way we know to save lives. However, there can be consequences to the normal transfer of commensal bacteria between the mother and child. The antibiotics can affect the mix of microbes a mother will have in her placenta, amniotic fluid and vagina. This disrupted maternal microbiome will then be “inherited” by baby from his mother.
Newborn babies are particularly susceptible to the effects of antibiotics on their gut bacteria. Their gut microbiome is still being established during the first two months of life. Taking antibiotics early on can disrupt the healthy colonization of their digestive tracts by good bacteria and instead allow for colonization by less healthy or even harmful microbes. Development of the baby’s immune system can be disrupted by this.
Cesarean sections have saved the lives of countless babies and mothers when used in emergency situations. Their use has increased dramatically and the concept of an elective C. section, where a mother chooses to have one without significant medical reason to do so, is becoming common. According to the US National Center for Health Statistics, 1 in 3 births in the US are now by C. section which is up 60% since 1996.
From a pure financial cost perspective, a C. section is more expensive than a vaginal delivery and is one reason that medical and insurance costs have risen. There now appears to be a health cost to the babies who are born this way as well.
When the baby is delivered via an incision through the mother’s abdomen, he does not receive the extended exposure to his mother’s vaginal microbiome that he would otherwise get. Instead, he is initially exposed to the microbes found on the medical staff’s hands and in the hospital operating room and later to those found on his mother’s skin. These environmental microbes then can go on to colonize the infant’s relatively microbe-free digestive tract. The resulting mix of microbes is very different from those found in the mother’s vaginal canal, which have evolved over time to benefit the infant.
It has been shown that babies born by C. Section have reduced bacterial diversity and lower levels of good bacteria than those that are found in babies delivered via the birth canal. This can hinder digestion and negatively affect the developing immune system and may even contribute to other behavioral and developmental conditions.
A verifiable, statistically significant increase in risk of developing certain health conditions has been observed for people born via C. section. A child born this way is at greater risk of developing allergies, food allergies and asthma. Celiac disease and Type-1 diabetes, each auto-immune diseases, are other illnesses that are statistically more common in births by C. section. Birth by C. section even raises the risk of later obesity, which is also linked to the mix of microbes in the gut. The greater risk of these conditions highlights the importance of the transfer of microbes from mother to child and stems from the critical role that the gut microbiome has in developing the immune system.
Establishment of a Healthy Microbiome in an Infant (Microbirth) is Important
This brings us back to the initial question: with everything else there is to be concerned about as expectant parents, do we need to worry about our child’s microbiome both during pregnancy and after birth? The short answer is “yes”, but the more nuanced one is, “it depends.”
Given that the transfer of health-promoting, commensal microbes from mother to child plays such an important role in the development of the immune system and childhood and adult health, it is important for a mother to consider her infant’s microbiome, when making decisions, both before birth and for the first several months after.
How do I Protect my Child’s Microbiome?
In most cases, a mother does not need to do anything special to ensure that her newborn’s digestive tract is colonized by health-promoting microbes (bacteria and beneficial yeasts). If the mother has good gut health, does not have a vaginal infection, has a strong immune system, and has not taken antibiotics during pregnancy or during early breastfeeding, then odds are very good that mother already has a healthy microbiome, which will be passed along to her infant during birth and subsequent breastfeeding.
In some situations, however, the microbiome must be given due consideration and steps should be taken to improve the health of the microbiome for Mom and baby.
Mother’s Gut Microbiome is Unhealthy
A woman planning on getting pregnant may suspect that she has an unhealthy microbiome. This can arise from stress, excessive alcohol use, having taken antibiotics in the past year or a diet high is processed foods and low in fiber. A future mother may suspect that her gut microbiome is out of balance if she is having chronic digestive issues (diarrhea or constipation), she craves a diet high in carbohydrates and/or she is obese. Excessive anxiety not primarily caused by life stresses can be another indicator of unhealthy gut microbes for certain people.
There are simple steps to take to improve gut microbiome health. A mother should consider doing these before getting pregnant or early on in pregnancy if she suspects there might be a concern.
Eating foods that contain probiotics can quickly improve gut health. Naturally probiotic rich foods include:
- Kefir (preferably home fermented) is the king of the probiotic foods
- Yoghurt (provided it contains live, active cultures – read the label to be sure)
- Buttermilk (uncooked only)
- Sourdough Bread
- Soft Cheese (either aged or containing raw (unpasteurized) milk)
- Cultured Cottage Cheese
- Miso (Japanese dish of fermented soy beans)
- Kombucha (fermented sweet tea drink)
- Tempeh (Indonesian fermented soybean patty)
- Sauerkraut (labeled as containing live cultures or unheated)
- Kimchi (Korean dish of fermented and pickled cabbage)
Eating foods that nourish healthy commensal microbes helps them to thrive. Prebiotics are non-digestible carbohydrates (fiber) that remain in your digestive tract that the probiotics eat. Prebiotics are found in whole grains, vegetables and fruits and legumes. Even chocolate contains them – perfect for a pregnant woman’s cravings! During my first pregnancy I craved chocolate, and maybe I should have listened more to those cravings afterall.
Although eating foods high in probiotics is the best way to obtain them, it probiotic supplements can also provide a benefit to an unhealthy gut. Choosing a high-quality, fresh probiotic from a reputable producer and reputable seller is the best way to get results.
Cesarean section is the most common surgery in the United States and rates are increasing each year. This is happening even though medical guidelines discourage, it except in cases where it is medically required. There is compelling evidence that birth by C. section can raise a child’s risk of later development of allergies, auto-immune diseases and obesity. For this reason, a mother considering an elective C. section should do her homework and weigh the consequences of this decision carefully.
If a doctor is recommending a scheduled C. section and a pregnant woman is not sure if it is medically indicated, she should consider getting a second opinion on the matter from an expert in obstetrics and delivery. She should also ask questions and make sure she is comfortable with the explanations.
An emergency C. section is another matter altogether. Concern over a baby’s microbiome should not prevent a surgery that will potentially save mother or baby’s life.
Establishing a Healthy Microbiome following C. Section
It is possible for a baby can still establish a healthy microbiome in the absence of a vaginal delivery.
A baby’s first dose of microbes, albeit in relatively small amounts, come in utero from the placenta and a large dose comes in the breast milk and mother’s skin. A nursing mother can ensure that her milk is probiotic-rich by eating a diet high in naturally-occurring probiotics, discussed above, and even taking a high quality probiotic supplement.
Additionally, also as mentioned above, a pregnant woman’s vaginal microbiome changes in preparation for the birth. Dr. Karen Levy, a microbiologist, convinced of the importance of her baby’s exposure to these beneficial microbes, planned on swabbing her baby’s mouth and nose with her vaginal fluids immediately after her birth, when she was informed that her breech baby needed a C. section delivery. Fortunately for her, her daughter switched position at the last moment and was born via the birth-canal. (I highly recommend reading her article, linked to in the prior sentence. It’s very interesting).
Some preliminary research done by Dr Maria Gloria Dominguez-Bello, a microbiologist at NYU, has shown that placing gauze in the mother’s vagina while the Cesarean Section surgery takes place, allowing it to soak up the microbes that the baby would have been exposed to during a trip down the birth canal, and then rubbing the gauze thoroughly all over the newborn’s skin as well as swabbing its eyes, mouth and nose with the vaginal bacterial laden gauze appears to seed healthy bacterial colonization for the baby. Babies born via C. Section that were inoculated with the bacteria from their mother’s birth canal went on to develop microbiomes that more closely resembled babies born naturally. Long-term studies are in process to evaluate whether those treated infants also have lower rates of health concerns more in line with babies born naturally versus via C. Section.
Some patients are not waiting for the results to come out before trying the gauze technique themselves, figuring that if the baby had been born naturally, there would have been no went to prevent exposure to the very same microbes being collected and swabbed on the baby. As research is ongoing on this seemingly obvious yet also radical intervention, a mother should not attempt to transfer microbes from her vagina to the baby without first consulting with and getting agreement from her obstetrician and pediatrician and should understand and feel comfortable with the fact that the consequences are not fully understood medically.
As discussed above, breast milk contains health-promoting, commensal bacteria that can help an infant establish a strong microbiome. This is yet one more reason to strongly consider breast feeding whenever possible. The physical process of nursing also introduces beneficial microbes from the mother’s skin to the infant’s gut microbiome.
If a non-breast feeding newborn does not receive a full complement of beneficial microbes from his mother, this partial void leaves an opportunity for other microbes that the baby comes into contact with from the environment to colonize the gut – in a different mix of species and in different proportions than they would have gotten. Although the environmental microbes may not all be harmful, the baby may end up missing out on certain species that are important for the immune system.
If breast milk is not a possibility, perhaps because of healthy issues or because of adoption, skin to mouth contact between mother and baby can still transfer some of the mother’s healthy microbes to the baby even if the baby is formula fed. In certain metropolitan areas, there are breast milk banks where mothers with extra milk donate the excess for babies who do not otherwise have access to human breast milk.
Research is currently underway in the US to evaluate the efficacy and safety of giving probiotic drops to infants, although they are currently prescribed and used in Europe to reduce colic. There is no definitive evidence at this time, although studies are underway, that seem to show that this can be beneficial for babies born via Cesarean section.
Antibiotics kill bacteria indiscriminately, both good probiotic ones and bad.
Sometimes it is necessary for a mother to take them either during pregnancy or following her baby’s birth to fight a dangerous bacterial infection. Although this may affect her gut microbiome and the bacteria in the milk, she can take a probiotic during and after antibiotic treatment as well as making sure her diet is rich in probiotic and prebiotic foods. This will assist her microbiome and commensal bacteria to spring quickly back to health.
As a baby’s microbiome is very fragile for the first few months of life, while it is being established. A course of antibiotics early on can disrupt, sometimes severely, his microbiome. But as stated, sometimes they are necessary to save a baby’s life. However, they should not be given indiscriminately to infants unless there is clear need and benefit to be received. As a parent, it is important to ask questions of a doctor and find out if there are any safe alternatives to prescribing antibiotics to your baby.
My son was given strong antibiotics during the first few weeks of life for a dangerous lung infection. His microbiome was disrupted, as evidenced first by colic and then by extreme picky-eating that lasted for many years until we returned his gut to a healthier state. In his case, it was strongly suspected at the time of illness that the lung infection was viral and if that was true, the antibiotics would not have been able to fight the infection anyway as they only fight bacteria – not viruses! However, as a parent with a desperately sick child, even knowing what I know now, I do not know that I would have done anything differently.
If antibiotics are given to a very young infant, it may beneficial for a breastfeeding mother to increase her own intake of probiotics and probiotic rich foods to ensure that the milk she is producing is high in beneficial microbes. She should also continue to breastfeed through any subsequent colicky symptoms as the microbes they contain may eventually decrease the problem.
My first reaction, upon hearing about the film Microbirth, was to feel that it was an unfortunate movie that would prey on the anxieties of new parents, who are already feeling nervous and overburdened by all of the guilt and paranoia inducing messages that exist for expectant mothers and father. However, upon further reflection, I actually believe that the important message of the film is one of empowerment.
There is much that we can do as parents, by ensuring a healthy transfer of microbes from mother to infant, to improve the long-term health and development of our babies. Giving the parents the understanding of how healthy immune systems evolve gives them powerful knowledge. Using this knowledge to make better decisions to maximize our children’s health and well-being can give a lifetime of pay-off for both our children and for us.
I hope the film gets lots of appropriate attention and has an impact on how medical decisions are made as well as spurring more needed research into this area.
As always, I welcome your comments and shared experiences below.