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Pregnancy and Birth, and the Gut Microbiome

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Pregnancy and the microbiome — The American Microbiome Institute. There have been a number of studies that discuss the importance of the microbiome transfer between mother and child; however few studies have looked into the changes that occur to the mother's vaginal microbiome during pregnancy.

Pregnancy and the microbiome — The American Microbiome Institute

A new paper published in the journal Microbiome by AMI Scientific Advisory Board member Dr. Rite of Passage. Anna Simonsen-Meehan felt robbed.

Rite of Passage

Advised by doctors to plan a cesarean delivery for her first child, she had wanted desperately to give birth naturally. But Anna and her husband were determined not to let their son’s surgical entrance into the world rob him of the profuse coating of bacteria babies normally acquire during their passage through the birth canal. Within a minute or so of their baby’s December 2015 birth, new father Joseph Meehan took a piece of gauze that had been soaking in his wife’s vagina just before surgery and methodically swabbed it across their son’s 8-pound body — starting with his lips, nose, and hands, then working his way down to the infant’s back and genital area.

Gut microbiota and pregnancy. As we have previously explained in this blog, many factors can alter our gut microbiota: from health status and diet to ageing and pregnancy.

Gut microbiota and pregnancy

Confirming this, a study published recently in Cell Magazine showed that the composition of gut microbiota changes dramatically while expecting a baby. Although gut microbiota was widely analyzed up to now, this was the first time that the gut microbe population has been tracked during pregnancy. Researchers wanted to explore and characterize the evolution of gut microbiota composition during pregnancy. They discovered that women’s gut microbe populations change significantly as pregnancy advances, losing diversity. By the third trimester it looks very much like the one from a person who is overweight and has an increased risk for diabetes, but these changes, as it is concluded in the research “are associated with metabolic disease in nonpregnant women and men but may be beneficial in the context of a normal pregnancy”. Interested in reading more? Pregnancy & early life - Gut Microbiota for Health. The Impact of a Western Style Diet During Pregnancy.

Taylor Soderborg is a 3rd year MD/PhD student at the University of Colorado Denver, School of Medicine, pursuing a PhD in integrative physiology: reproductive sciences track.

The Impact of a Western Style Diet During Pregnancy

Her thesis work is focused on the influence of maternal diet-induced obesity on development of the infant microbiome and how this may alter immune system development and later life obesity. She plans to pursue the obstetrics and gynecology clinical specialty. Soderborg presented her work in poster format at the recent Keystone Symposium: Gut Microbiota Modulation of Host Physiology. Later, she answered some questions about her work for GMFH editors. Taylor Soderborg, MD/PhD student, University of Colorado Denver. Neurodevelopmental Disorders Linked To Disrupted Fetal Brain Immunity. Disrupted fetal immune system development, like that caused by viral infection in the mother, may be a key factor in the later appearance of certain neurodevelopmental disorders, according to a study from the Weizmann Institute.

Neurodevelopmental Disorders Linked To Disrupted Fetal Brain Immunity

The finding may explain how a mother’s infection with the cytomegalovirus (CMV) during pregnancy, which affects her own and her fetus’s immune system, increases the risk that her offspring will develop autism or schizophrenia, sometimes years later. This increased risk of neurodevelopmental diseases had been discovered many years ago in epidemiological studies and confirmed in mouse models. The Weizmann study, led by Dr. Ido Amit and Prof. The placental microbiome — The American Microbiome Institute. Microbiome populations have been well-characterized in many distinct body-sites.

The placental microbiome — The American Microbiome Institute

Interestingly, there is a lack of knowledge in the microbiome of the placenta, an environment that was long thought to be sterile. Investigating the placenta is important toward understanding the microbiome in human development, especially in light of previous evidence demonstrating that human microbiota populations fluctuate extensively in the first year(s) of life. The placenta is the cradle of life for fetal development, leading researchers from Baylor School of Medicine to study the microbiome of this tissue.

Placenta samples were collected and analyzed to characterize the placenta microbiome, and explore links to fetal development and microbiome compositions. 320 placenta specimens were collected, and PCR was used to characterize bacterial populations. The researchers also demonstrated an association between placental microbiome composition and healthy births or births with complications. The placenta harbors a unique microbiome. Contrary to the common idea of a “sterile” intrauterine environment, Aagaard and coauthors demonstrated the presence of a microbiome in placentas from 320 healthy pregnancies, collected under sterile conditions.

The placenta harbors a unique microbiome

This microbiome was quite different from that reported in other parts of the mother´s body including the vagina and the gut, and resembled more the microbiome of her oral cavity, however in much lower abundance. This raises the question – without being able to answer it yet – whether bacteria ingested via food of mothers are able to affect the microbiome development of the baby even before delivery. An altered placental microbiome was associated with antenatal oral infections, that in turn may have resulted in preterm deliveries. Source: Kjersti Aagaard et al. Microbe Translocation and Colonization in the Womb.

How might microorganisms move from one part of the body to another?

Microbe Translocation and Colonization in the Womb

Let’s begin with the womb, where the concept of fetal colonization has rapidly gained acceptance, indicated by meconium and placental microbe studies. A new stool study reveals virus populations are dynamic in healthy infants. The infant virome is most diverse early in life, then bacteria flourish as viral counts decline. Most interestingly, the main types of viruses were identified as bacteriophages. These viruses infecting bacteria were found richest and most diverse in early life. How do translocated maternal gut microbes affect fetal gut-brain development? LBP and LPS are studied related to Parkinson’s, schizophrenia, and amyloids in Alzheimer’s. Evidence to date is compatible with the hypothesis that fetal gut microbes are of maternal intestinal origin via chylomicrons. References: Mouse study sheds light on how mom’s gut microbiota during pregnancy shapes the immune system of her offspring - Gut Microbiota for Health.

Babies are born with immature immune systems.

Mouse study sheds light on how mom’s gut microbiota during pregnancy shapes the immune system of her offspring - Gut Microbiota for Health

Until now, it was believed that the birth process was the first opportunity for microorganisms from the mother to colonize the baby’s gut and, thus, to shape the immune system. Now, a team formed by German and Swiss scientists have discovered that this interaction with the baby’s immune system starts much earlier than previously thought: during pregnancy. According to their findings, published in Science magazine, some molecules produced by the gut microbiota and/or non-living bacterial fragments are transferred from the mother to the baby through the placenta or, later, through antibodies present in breast milk.

These molecules and fragments may stimulate immune cells in the newborn to prepare it for coping with microorganisms living in its own gut. “We did not find [live] bacteria, [either] in the placenta [or in] the foetus. Indeed, the groups of animals presented different patterns of gene expression in their intestines. References: Should women with gestational diabetes mellitus use probiotics? - Gut Microbiota for Health. Gestational diabetes mellitus (GDM) is one of the most frequent metabolic complications of pregnancy and its prevalence is up to 12% in developed countries.

Should women with gestational diabetes mellitus use probiotics? - Gut Microbiota for Health

Nowadays, several studies are investigating new therapies for glucose control that may complement diet, exercise, and pharmacological therapies. Among them, probiotics potentially represent a novel way to improve maternal metabolic and pregnancy outcomes. However, there are scarce randomized controlled trials (RCTs) to date that have directly investigated the glycemic effects of probiotics among women with GDM. Antibiotic exposure during pregnancy may increase risk of obesity in children — The American Microbiome Institute.

Caesarean sections, breast feeding, and the microbiome — The American Microbiome Institute. There is a growing amount of literature on the subject of babies' microbiomes because it is clear that the first few years of life are crucial to the development of the immune system, and poor development can have lasting, life-long consequences. As we have learned, a healthy microbiome is absolutely critical to a healthy immune system. Evidence for this connection is vast, but starkly manifests itself in germ-free mice which can not survive long due to autoimmune disease. So, as the thinking goes, a healthier microbiome as a baby leads to a healthier life. In any case, a commentary was recently written by AMI Scientific Advisory Board members Maria Gloria Dominguez-Bello, Rob Knight, and a colleague that discusses how delivery mode and infant feeding affect babies' microbiomes.

Elective vs. acute c-section deliveries: does it make a difference? — The American Microbiome Institute. Conducting a population based study of 750,569 children born between January 1997 and December 2012, they analyzed children born via elective c-section, acute c-section, and those born vaginally as the reference. They found that the children born by either elective or acute c-section had a higher risk of asthma, laryngitis, and gastroenteritis though electively born c-section babies had a more pronounced risk than acute c-section babies. Those born via elective c-section had an increased risk of lower respiratory tract infection and juvenile idiopathic arthritis. Study finds that C-sections are not a risk factor for IBD — The American Microbiome Institute.

The logic behind this hypothesis is that birth by vaginal delivery would expose the infant to the mother’s vaginal bacteria, which could possibly be essential in the development of the infant’s own microbiome. To study whether C-sections are a risk factor for IBD, the researchers gathered data from the University of Manitoba IBD Epidemiology Database, which keeps health records of all Manitobans diagnosed with IBD between 1984 and March 2010. These records were matched with birth and maternal health records. 1,671 IBD patients were linkable with mothers and therefore used for analysis. 10,488 matched controls were also used.

Analysis showed that IBD patients were no more likely to be born by C-section than the controls. Additionally, urban rather than rural residence was associated with higher instances of IBD. What happens if you give c-section babies a vaginal microbiome? — The American Microbiome Institute. Babies born by cesarian section have greater likelihoods of autoimmune diseases during childhood and later in life. They also have a gut microbiome that resembles their mother’s skin right after birth. On the other hand, babies that are born vaginally have a gut microbiome that resembles their mothers’ vaginas, and are at lower risk for asthma and allergies. Given the importance of the microbiome on immune development, many scientists believe that there may be a link between mode of delivery, the initial infant gut microbiome, and normal immune development.

One possible method to ensure a baby that is born by c-section is initially colonized by his or her mother’s vaginal microbiome is to swab the mother’s vagina and transfer her microbiome to the baby immediately after birth. Opinion: A Mother’s Microbes. ISTOCK, FAIRYWONGAs parents, we all want what’s best for our kids. However, it’s not always clear what that is. At every turn, we are faced with questions where the answers are not yet known or are unknowable. Experts call for caution among parents who carry out vaginal seeding - if uncontrolled, it may place newborns in danger - Gut Microbiota for Health.

Startup Licenses “Vaginal Seeding” Approach. Boston-based Commense plans to develop microbial and nonmicrobial interventions aimed at improving child health. Clinical implications of recent study exploring 'microbial restoration procedure' for caesarean-born infants - Gut Microbiota for Health. Mode of delivery is known to influence the microbiota composition of newborns. Asthma could be brought on by maternal diet and lack of bacterial metabolites — The American Microbiome Institute. Maternal HIV Infection Affects Microbiome Of HIV-uninfected Infants. Vaginal microbiome during pregnancy. iHMP blog #2 — The American Microbiome Institute. The vaginal microbiome undergoes many changes during pregnancy, and it has been associated with various afflictions, such as gestational diabetes, low birth weight, necrotizing enterocolitis, and colic.

Bacterial vaginosis associated bacteria may increase a women’s risk for miscarriage — The American Microbiome Institute. Bacterial infections or even slight imbalances can be damaging at many difference locations in the human body. One that should be taken seriously in bacterial vaginosis, which is an infection in females where a healthy bacterial balance is taken over by bacteria such as Gardnerella vaginalis, Ureaplasma urealyticum, and Mycoplasma hominis to name a few.

Maternal stress alters offspring gut and brain through vaginal microbiome. Characterizing the “Healthy” Vagina. FLICKR, GREENFLAMES09For years, researchers characterized the microbial community of women’s vaginas as being dominated by Lactobacillus bacteria, which ferment carbohydrates to lactic acid, yielding a low pH that is toxic to many pathogenic microbes.

Vaginal microbiome once again tied to preterm birth — The American Microbiome Institute. Preterm birth is major global health challenge. Today, around 11% of all babies are born prior to 37 weeks, and are considered preterm. Many of the causes of these preterm births are still unknown, but it is thought that around 25% of them may be related to a bacterial infection that comes from somewhere in the mother’s own body, i.e. her microbiome. Reduced incidence of atopic dermatitis in children  Maternal stress could alter a newborn’s gut and brain