Introduction:
The mother's body experiences changes in hormones, immunity, and metabolism throughout pregnancy to promote fetal development. Pregnancy is a complex and sensitive process. Human microbiomes are primarily found in the intestines and comprise between 500 and 1,500 distinct types of bacteria, archaea, fungi, and viruses. The gut microbiome will undergo significant alterations throughout pregnancy. The mother's and the fetus's health can be improved by controlling gut microbiomes. Numerous pregnancy issues, including gestational diabetes, obesity, preeclampsia, digestive problems, and autoimmune diseases, are linked to gut microbiomes. Additionally, the colonization of microbiomes in the early life of infants is directly tied to the microbiomes in the mother's milk and vagina. The maternal microbiomes include a pregnant person’s gut, skin, and vaginal microbiomes.
How Does the Maternal Microbiome Influence the Neonatal Microbiome?
The birth process influences the microbial colonization of the child's intestine and is impacted by the characteristics of the mother's microbiome, manner of delivery, familial, and other perinatal variables. Infants born via cesarean delivery get germs similar to the mother's skin microbiome, whereas those born via vaginal delivery acquire microorganisms similar to the mother's vaginal microbiome. The newborn's size and gestational age have an impact on the microbiota of the baby as well. Preterm children exhibit a predominance of Proteobacteria rather than two of the major bacterial species found in healthy term infants (Bifidobacterium and Lactobacillus).
Infants begin to acquire body site-specific microbiomes during the first month of life, with eating habits significantly impacting the composition of the gut microbiome. Breastfed infants have a significantly more abundant microbiome in Bifidobacteria, which is thought to enhance immunological function. The type and timing of complementary food introduction in the first year affect the microbiome's makeup; the earlier introduction is connected to significant microbiome changes that increase the risk of gastrointestinal infection. The microbiome changes with each dietary transition during the first two to three years of life. Antibiotic use and hospitalization impact the gut microbiome's composition and are linked to a significant loss of diversity. Recent research indicates that the fetal microbiome may even start to colonize while the fetus is still inside the mother, further highlighting the critical function of the mother microbiome in neonatal and infant health.
How Does the Vaginal Microbiome Affect Pregnancy Outcome and Affects Infant Health?
More than 50 non-pathogenic bacteria species reside in the vaginal tract. The vaginal microbiota differs greatly among reproductive-age women who are asymptomatic. An increasing body of research shows that the vaginal microbiome affects the risk of preterm birth. Sexually transmitted illnesses, bacterial vaginosis, urinary tract infections, and HIV can all be avoided by maintaining a healthy vaginal microbiota. The vaginal microbiota linked with bacterial vaginosis increases the incidence of sexually transmitted diseases, raising the risk of preterm birth.
What Elements Affect Maternal Microbiome Before and During Pregnancy?
Before Pregnancy:
Anthropometric factors (such as body mass index), pharmaceuticals (such as antibiotics and proton-pump inhibitors), illnesses (such as type-2 diabetes), environmental factors (such as smoking), and food (such as the Mediterranean diet) are all significant factors that influence the adult gut microbiome. It is interesting to note that several early life characteristics, such as nutrition, lifestyle, physical activity, living in an urban environment, and exposure to pets, have a long-lasting impact on the gut microbiome. Similar to current exposures, prior exposures like smoking at any time in life can affect the gut flora for a very long time. During pregnancy, several of these factors still impact the gut flora. It has been demonstrated that pre-existing conditions, such as hyperthyroidism, are linked to OTUs during pregnancy. The gut ecology exhibits severe dysbiosis (an imbalance in the gut flora’s diversity) in diseases such as inflammatory bowel disease (IBD).
During Pregnancy:
Maternal diet, both before and during pregnancy, is linked to changes in the gut microbiota related to pregnancy. Additionally, it has been demonstrated that maternal changes in gut flora are related to before-pregnancy weight and pregnancy weight increase. Additionally, previous pregnancies may influence the mother's gut flora during pregnancy. Also proven to affect the microbiome during pregnancy include the usage of pre-and probiotics as well as antibiotics, proton pump inhibitors, laxatives, and Metformin.
What Are the Maternal Gut Microbiome Effects on Mother and Newborn Well-Being?
Gestational Diabetes Mellitus:
Increased insulin resistance, dysfunctional pancreatic beta-cells, and spontaneous pregnancy-related hyperglycemia are all symptoms of gestational diabetes. Globally, its prevalence ranges from 5.4 % to 14 %. The majority of research on the connection between the gut microbiome and GDM reports that GDM women's gut microbiota differs from that of healthy pregnant controls. At the same time, there needs to be more agreement among studies in this area.
Preeclampsia:
New-onset hypertension, proteinuria, and end-organ dysfunction of organ systems, such as the liver and central nervous system, are the main characteristics of preeclampsia. Recent research has revealed that PE alters the composition of the gut microbiome. However, the size of these investigations, which used 16S rRNA sequencing, is small.
Microbiome of the Mother’s Gut and Child Health:
According to research, the maternal gut microbiota has been linked to maternal and baby health outcomes, including prenatal neurodevelopment. The maternal microbiota has implications on newborn health beyond neurodevelopment. The maternal microbiota shapes the offspring's metabolic system through compounds such as SCFA, as demonstrated in a mouse study. Finally, some evidence connects the microbiota of the mother's gut to allergy illness in human offspring. Prevotella copri's presence in the mother's gut during pregnancy predicted a reduction in IgE-mediated food allergy in the offspring, according to research by Vuillermin et al. using 16S rRNA sequencing.
Why Is It Important to Modify the Gut Microbiome?
Given the growing number of links between the maternal gut microbiome and outcomes for mothers and babies, modulating the gut microbiome presents an alluring target for illness prevention. This has resulted in an increase in pre- and probiotic therapies, with probiotics now being the most well-studied, targeted at preventing various pregnancy problems and optimizing baby health outcomes. Furthermore, it was discovered that probiotics increased the risk of PE while not affecting the weight gain of pregnant women. There is a need for systematic evaluation of the impacts of probiotic products, utilized independently or in conjunction with pharmaceutical and nonpharmacological measures, on the prevention of pregnancy complications due to the substantial variation in intervention studies in regards to the probiotics used, their length of use, and the problems studied.
Conclusion:
The maternal microbiome has been highlighted as a critical driver of various essential mother and child health outcomes, and it influences the infant microbiome in conjunction with perinatal variables. The gut flora changes throughout pregnancy due to food, drugs, weight gain, smoking, and parity. Preeclampsia and gestational diabetes are problems that have ties to the maternal gut flora. Large follow-up studies are essential to comprehend the causes and mechanisms of pregnancy complications.
