During early life, the gut microbial composition rapidly changes by maternal microbiota composition, delivery mode, infant feeding mode, antibiotic usage, and various environmental factors, such as the presence of pets and siblings. An integrative study on the diet, the microbiota, and genomic activity at the transcriptomic level may give an insight into the role of diet in shaping the human/microbiome relationship. Disruption in the gut microbiota (i.e., gut dysbiosis) has been linked to necrotizing enterocolitis in infancy, as well as some chronic diseases in later, including obesity, diabetes, inflammatory bowel disease, cancer, allergies, and asthma. Therefore, understanding the impact of maternal-to-infant transfer of dysbiotic microbes and then modifying infant early colonization or correcting early-life gut dysbiosis might be a potential strategy to overcome chronic health conditions.
∙ Microbial colonization primarily occurs after birth but there may be some colonization in utero, although this remains highly controversial.
∙ Maternal factors during pregnancy affect the infant microbiota: diet, weight, gestational weight gain, and antibiotic usage.
∙ Microbes are passed from mother-to-infant during and after birth. Delivery mode, breastfeeding, early life antibiotic, and proton pump inhibitor treatment have the largest effects on microbial composition in early life.
∙ The early life gut microbiome plays an important role in the development of the immune system and metabolism.
The collection of bacteria, archaea, and eukarya colonizingthe gastrointestinal tract is termed the "gut microbiota." [
The uterus and fetus are considered sterile environment unless clinical infection occurs, such as in chorioamnionitis; however, a growing body of evidence indicates that the intrauterine environment is not sterile but that maternal-fetal transmission of microbiota occurs during pregnancy. Nonpathogenic bacteria are detected in the placenta, umbilical cord [
Obesity is characterized by an imbalance in the
Maternal weight status might also affect maternal milk composition [
Longitudinal cohort data showed that a maternal high-fat diet altered early bacterial colonization independent of maternal obesity. In association with a maternal high-fat diet, the neonatal meconium microbiome varied with a significant immediate relative depletion in
Antibiotic exposure during gestation has an extensive effect on the microbiome by reducing microbial load and altering composition as well as long-term influences on the developing infant gut microbiome [
Maternal allergies may affect the microbiome of the breast milk. Depleted levels of
Low to moderate levels of ethanol exposure in combination with artificial sweeteners reduced
Early life exposure to maternal and environmental smoke increased the levels of
Air pollution is hypothesized as a potential factor of neonatal gut dysbiosis, particularly the depletion of the Firmicutes phylum [
Jašarević et al. [
Gestational diabetes mellitus-related dysbiosis can be vertically transmitted to the offspring. Increases in
Several studies have shown relatively favorable effects of probiotic administration during the perinatal period [
The mode of delivery is generally accepted as a major factor determining initial colonization [
Gestational age at delivery impacts the bacterial microbiota [
Microbial colonization of the infant gut occurs rapidly after birth and is influenced by delivery mode, feeding, and many other factors, such as environmental factors (including geographic location) and household exposure (e.g., siblings and furry pets). The infant microbiota composition changes rapidly in the first weeks following birth and then stabilizes until the infant is weaned off an exclusive milk diet and started on solid foods.
Recent studies reported that human milk is not sterile and is a primary and main factor that drives the acquisition and evolution of the gut microbiota in early life [
Antibiotic administration is another major factor that interferes with the composition of the gastrointestinal microbiome. In particular, antibiotic exposure within 1 month of birth alters the balanced development of the microbiome momentarily and persistently [
The impact of proton pump inhibitors (PPIs) and other acid-blocking medications in young infants is gaining more attention, as disturbances in the microbiome have been reported. PPI usage for 8 weeks resulted in a decrease in
Intervention with probiotics as a means of maintaining a healthy gut ecosystem in early life has become popular. In attempts to mimic the composition of human milk, the design of some infant formulas includes the addition of probiotics. It is important to note that not all probiotics are equally safe, and the effects demonstrated from one strain cannot be extrapolated to another strain, even if they belong to the same species [
Supplementation with bifidobacteria strains to infant formula from birth does not seem to compensate for the differences in gut microbiota composition observed between breastfeeding and formula feeding in early life in full-term infants [
Adding LGG to an extensively hydrolyzed casein-based commercially available formula designed for infants at high risk for allergic manifestations associated with immunoglobulin E-mediated cow's milk allergy reduced the incidence of other allergy manifestations and improved the development of oral tolerance to cow's milk [
A recent review of clinical trials and case studies that evaluated several probiotics (e.g.,
Although human milk is rich in prebiotics (HMOs), bovine milk also contains oligosaccharides, some of which are structurally similar to HMOs. Attempts are being made to stimulate the growth of bifidobacteria and lactobacilli in the infant gut to levels detected in breastfed infants by the addition of various kinds of prebiotics (e.g., fructo-oligosaccharides and galacto-oligosaccharides) to infant formula [
The impact of breastfeeding on the microbiome after weaning from milk to solid food is correlated with the duration of exclusive breastfeeding rather than the age at which weaning occurs [
Maternal and infant factors can influence the composition and development of the infant gut microbiota. Microbial colonization primarily occurs after birth, but there may be some colonization in utero, although this remains highly controversial. Maternal factors during pregnancy that can affect the infant microbiota include maternal diet, weight, gestational weight gain, and antibiotic usage; however, their overall impact is low compared to that of birth mode, infant diet, and antibiotic treatment. Microbes are passed from the mother to the infant during and after birth. Delivery mode, breastfeeding, and intrapartum and early life antibiotic treatment have the largest effects on microbial composition in early life.
The early life gut microbiome plays an important role in the development of the immune system and metabolism. Emerging data demonstrating the importance of early life gut microbiome development as a protective factor against gut dysbiosis-related diseases later in life support the rationale for targeted therapies to restore the early life gut microbiome.
Therefore, understanding the impact of maternal-to-infant transfer of dysbiotic microbes and then modifying infant early colonization or correcting early life gut dysbiosis is a potential strategy to overcome chronic health conditions.
No potential conflict of interest relevant to this article was reported.
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Maternal factors on the infant gut microbiome and its implications on childhood health. health. BMI, body mass index; HMO, human milk oligosaccharide; NAFLD, nonalcoholic fatty liver disease.
Factors influencing the development of the infant microbiota.
Factors shaping the intestinal microbiota.
Early-life factors and dysbiosis in neonatal gut microbiome.
Microbes identified in human milk
Staphylococci |
Streptococci |
Corynebacteria |
Propionibacteria |