Mother and child - the microbiome connection
How bacteria ensure the survival of the human race
The essential characteristic of all life is successful reproduction and thus the passing on of genetic material. In the case of bacteria, this is achieved quite simply by dividing into two. The bacterium grows and then divides into two identical cells. Viruses, on the other hand, do not reproduce on their own but always require a host, whose energy and production facilities are then taken over by the virus. Therefore, strictly speaking, a virus is not a life form but exists only "at the edge of life". Humans, on the other hand, have established a complex system over time that allows them to form a new being within themselves, nourish it and then release it into the environment: pregnancy.
For us, humans, this is a very natural process. But in fact it is very complex and the success depends on various factors. We all remember well the horror trilogy "Aliens", where an extraterrestrial being is implanting itself in humans, feeding on them and then bursting them from the inside during the process of birth. A bloody affair. I can still remember well when I had watched the movie trembling in the cinema in 1979 with a fake school ID and in my youthful view the process of the birth did not seem so dissimilar to me. In fact, however, it makes you realize how gracious Mother Nature has been to humans.
At the end of the process, the children crawl into her and begin to eat the mother from the inside
The spider species Stegodyphus dumicola did not fare quite so well. After the birth of the young, the mother begins to produce a liquid with which the offspring is fed. In the process, the mother visibly liquefies. At the end of the process, the children crawl into her and begin to eat the mother from the inside. I wonder if this was the template for the movie Aliens.
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The cesarean section
In humans, on the other hand, this is a very well-defined process in which the mother is basically allowed to survive and establish a mother-child relationship. The advantage is obvious: this allows her to care for her baby beyond birth and increase its chances of survival.
While pregnancies have been more or less the same for thousands of years, in recent centuries people have begun to influence the process. The aim was primarily to respond to emergency situations. In the Middle Ages, the Caesarean section was discovered, in which, by courageously intervening in the womb, at least the child could be saved. The myth says that the Roman emperor Caesar was cut out of his mother's womb and therefore this form of birth assistance was named after him. In fact, this type of rescue existed already centuries earlier. However, the mother always died in the process.
Caesar was cut out of his mother's womb
This procedure was improved more and more, so that nowadays the cesarean section has become enormously popular. In the U.S. and Germany, the percentage is about one-third, although only about 2% of C-sections in Germany are medically necessary. In Sweden, the percentage is quite low at 17%, and in Brazil it is very high at 56%. In the city of Rome, it is as high as 80%, because the average age of mothers here is quite high due to the lifestyle, and the women want to return to work very quickly.
But the studies of the past years have shown that one factor has not been taken into account: the microbiome of the mother and the transfer of the bacteria to the child.
Before we discuss the resulting dangers to the newborn, let's take a brief look at how the mother's microbiome develops during pregnancy. The microbiome, i.e. the totality of all bacteria on and in the human being, changes in its composition during pregnancy. It follows a clearly structured blueprint, the plan of which is to provide the child and the mother with sufficient nutrients during pregnancy and, in the end, to have the child supplied with bacteria. These are to accompany and protect the child during its further life.
The microbiome changes during pregnancy
During pregnancy, three hotspots of the woman's bacteria in particular change: the microorganisms in the intestine, in the vagina, and in the mouth. As we will see later, these are precisely the areas that are either relevant for a nutrient supply (intestine) or where there is a transfer of microorganisms during birth due to mother-child contact.
First of all, the microorganisms in the intestine change in a way that they can extract more energy, i.e. calories, from food. This makes evolutionary sense, because in times when there was little food available - and this was often the case with our ancestors - it helped to supply mother and child sufficiently. Nowadays, the increased energy supply in combination with an unfavorable diet can put the mother's system under tremendous stress and lead to gestational diabetes. In most cases, this disappears again after birth. In a few cases, however, mothers continue to suffer from diabetes after giving birth for the rest of their lives.
It is interesting to note that this specialization of the bacteria in the intestine continues to increase during pregnancy and thus the so-called alpha diversity continues to decrease. In evolutionary research, alpha diversity is a measure of the species diversity of a habitat. It describes how many species occur there.
The baby must not be put at risk.
Secondly, the bacteria in the vagina are also changing. The vagina is usually dominated by various lactobacilli, which ensure that no pathogenic, i.e. disease-causing, microorganisms grow. This is usually achieved by lowering the pH value, which only a few bacteria can handle. But the lactobacilli also secrete bacteriocins that kill other bacteria. This also increases resistance to viruses, such as HIV infection. If the balance of the flora is disturbed, vaginal dysbiosis can develop, in which mainly anaerobic bacteria spread, i.e. microorganisms that do not require oxygen, and thus stress the entire system.
During pregnancy, the composition of lactobacilli species in the vagina changes, making the flora even more stable and resistant to infections. This is excellently done by nature, because during pregnancy the vagina must prevent the invasion of pathogenic bacteria and also exclude infections that would stress the immune system and the body. The baby must not be put at risk.
Third, the oral microbiome is also changing and becoming more diverse. This is mainly due to the increasing production of progesterone and estradiol.
So we see that almost the entire bacterial composition of the mother is changing to allow the baby to survive and to ensure the offspring.
During natural birth, bacteria are transferred to the child at various points. This is extremely important because nature wants to ensure that exactly the right bacteria are present in and on the child right from the start. The microorganisms multiply and are thus the first colonizers, which all other bacteria must first push aside if they also want to grow. If this transmission did not take place, the child would in principle be exposed unprotected to any bacteria with which it would come into contact. It would therefore depend on luck, because there could be good and beneficial bacteria as well as harmful bacteria.
When the amniotic sac breaks during the birth process, the amniotic fluid is pushed through the vagina and serves as a "cab" for the lactobacilli, which then spread to the thighs and wait there for the newborn. They take over colonizing the skin providing a friendly welcoming committee. Meanwhile, in the uterus, the baby prepares for exit and powered by a flood of hormones rushing into the mother and baby, it is pushed through the internal cervix into the cervix uteri. From there, it moves on through the external cervix and is pushed out into the open through the vagina. In the process, it comes into contact with the bacteria in the vagina, some fecal germs, and the bacteria on the mother's thighs. Once delivered, the baby wants to suck on the mother's nipples. Since the infant's mouth is still full of lactobacilli, the first bacteria are immediately introduced into the intestine along with the milk. Lactobacilli possess the enzyme lactase, which can break down the lactose in breast milk. This prepares the baby perfectly for its food. The subsequent mother's kisses transfer more bacteria of the altered oral flora to the baby.
The whole process is a wonderful interaction of mother, child and bacteria.
Shortly after delivery, the baby is covered with a white layer, the vernix caseosa. This protects the baby's skin from pathogenic bacteria and supports the growth of good microorganisms. It consists of water, skin fat, epithelial cells, lanugo hair, and a variety of other substances, all of which are supposed to protect the still extremely sensitive skin of the newborn.
When I first became a father I was surprised at how pleasant the vernix caseosa smelled. It was like a mixture of Nivea cream and body oil. Unlike in the past, today in most hospitals this vernix caseosa is not wiped off right away but left on the baby for a while. In earlier times, mothers still licked their babies and thus brought more of their bacteria onto the baby. Many animals still do this today.
The whole process is a wonderful interaction of mother, child and bacteria.
The disruption of the natural balance
However, cesarean section destroys this sensitive balance of nature. The child is taken directly out of the womb and does not come into contact with the numerous and important lactobacilli from the vagina. Instead, the first inhabitants are bacteria from the skin and bacteria that happen to be in the air of the surgery room. Every contact of the cesarean baby with a hand and a blanket means first contact with unknown bacteria.
This massively disrupts the natural colonization process. Additionally, women undergoing cesarean delivery are often given antibiotics to prevent infection. As recently as 2014, 40% of women in the U.S. with cesarean delivery were given antibiotics during childbirth, meaning that newborns were also treated with antibiotics simultaneously during their initial contact with the bacteria. Here, experts have become more cautious today and try to avoid this procedure as much as possible.
Every contact of the cesarean baby with a hand and a blanket means first contact with unknown bacteria.
Similarly, in many countries the practice of dripping antibiotics into the baby's eye immediately after birth has been abandoned. Before antibiotics, silver nitrate was used for this purpose and both served to prevent a possible gonorrhea infection through the woman's vagina. This sexually transmitted disease is caused by the bacterium Neisseria gonorrhoeae and can lead to blindness of the baby in rare cases. Nowadays, women are screened increasingly for gonorrhea (tripper) before birth to avoid antibiotic exposure of the baby. In Sweden, for example, this has always been avoided. This is because it was suspected that the use of antibiotics was not as safe as thought. The antibiotics used are broad-spectrum antibiotics, which not only kill the specific infection germ, but also a large number of other helpful bacteria at the same time.
The devastating effect of antibiotics
Antibiotics can have a devastating effect on both the newborn and the fetus. One can imagine that especially at a stage when the newborn is beginning to establish its microbiome, the use of antibiotics is destructive and can push the microbiome in a completely wrong direction.
Antibiotics disrupt the changes in the microbiome during pregnancy and destroy the infant microbiome that is being built up.
Thus, it is now suspected that a large number of our new civilization diseases such as obesity, diabetes in children, hay fever, food allergies and others are caused by the administration of antibiotics during pregnancy, during childbirth or during the infant and toddler phase. Research is still in full progress here, but the pattern is clear: antibiotics, through their broad efficacy, disrupt the changes in the microbiome during pregnancy and destroy the infant microbiome that is being built up.
The Golden Standard of baby nutrition
Breast milk is also crucial for the proper development of the child's microbiome. It helps to increase the diversity of bacteria. Studies have shown that cytokines in breast milk interact with the developing microbiota of infants and thus have a decisive influence on their microbiology, immunology and metabolism. Cytokines are proteins that regulate growth and differentiation of cells. If a mother cannot suckle the baby, the administration of foreign breast milk has proven to be effective. In any case, breast milk is far superior to industrial ready-made food, even if the campaigns of the manufacturers claimed otherwise, and should be given as a source of nutrition as long as possible. Of course, the increasing poisoning of the environment plays a role and may also affect breast milk. Nevertheless, the gold standard of infant nutrition is mother's milk.
The uterus: not a sterile place?
The development of the baby's microbiome has been studied more and more intensively in recent years. The dogma that the fetus in the uterus is in a sterile environment has now being challenged. There are practically no sterile areas in humans. It was previously believed that the blood and lungs, for example, were sterile. This has long been disproved. Therefore, it would not be a surprise if the first colonization and establishment of the microbiome were also taking place in the womb.
There are practically no sterile areas in humans.
Studies indicate a low level of colonization of the healthy placenta. Through this, the unborn could receive their first bacteria. Members of the genera Lactobacillus, Propionibacterium and the Enterobacteriacea could be discovered in it. Animal experiments with calves have shown colonization of the unborn from the 5th month of pregnancy. It would be surprising if this were different in humans.
Taking medication during pregnancy is not a good idea
The whole processes show how evolution has created a perfect system to ensure the health of the baby. This is why most women refrain from taking medication during pregnancy. The horrible memories of the prescription of thalidomide to pregnant women which later led to the thalidomide scandal are still vivid. Somewhat more unknown but no less horrific was the administration of DES to pregnant women in the 1950s. Diethylstilbestrol apparently had few to no side effects and was considered safe. Approved by the authorities, it was prescribed to women as a remedy for morning sickness, among other things. Smiling babies on advertising posters seemed to indicate that their health was due to DES. Even when a large-scale study appeared in 1953 suggesting that the drug was not effective at all, it continued to be prescribed. Everyone was taking it - so it had to be safe. It wasn't until 20 years later that the true extent of the disaster became apparent: young women were more likely to get vaginal cancer, which is usually found only in older women. Also, women who had been exposed to DES as babies in the womb had a higher risk of being infertile or getting breast cancer. Men also experienced increased health problems such as cysts in the male genital tract.
Just because everyone is doing it, doesn't mean it's safe.
The experiences of thalidomide and DES were clear signs that even when drugs appear safe, they should not be given during pregnancy because they often have effects that are not seen until much later. It is all the more frightening that during the Corona pandemic, officials are recommending the administration of an experimental and novel vaccine to pregnant women. It doesn't take much fantasy to imagine that an mRNA vaccine that converts cells into factories that produce spike proteins at high levels, which then flood the body, could also have effects on the unborn child. It is incomprehensible how doctors can follow these guidelines. No one can know what the long-term consequences of this treatment will be. We remember the old principle: just because everyone is doing it, doesn't mean it's safe.
What we must not forget
The analysis of the microbiome during pregnancies and in newborn babies will remain an important area of research. Hopefully, given the massive impact of antibiotics on the infant microbiome, we should intervene as little as possible in the process of birth, which is perfectly orchestrated by nature.
Often, interventions that seem logical to us today may have their safety disproven by new studies in the future.
We are still at the very beginning of understanding the microbiome. We should not forget that!
Martin J. Blaser, Missing Microbes; How the overuse of antibiotics is fueling our modern plagues, Henry Holt and Company, New York.
Mesa MD, Loureiro B, Iglesia I, Fernandez Gonzalez S, Llurba Olivé E, García Algar O, et al. The evolving microbiome from pregnancy to early infancy: A comprehensive review. Nutrients. 2020;12:133. - PMC - PubMed