pregnancy and chıldhood

Nutrition plays an integral role in the healthy development of babies and children, with the first one thousand days acknowledged to be of exceptional importance. But our gut does more than just help us digest food. The gut microbiome is a critical component of health and metabolism for all ages, from early life to adulthood. The first three years of life are central for the formation of a child’s gut microbiome, with multiple factors playing a role in its development.  


As a pregnancy advances, inflammatory and immune changes alter the gut function and bacterial composition of the mother’s microbiome. The microbe profile of a mother’s gut is considered a contributing factor to the health and wellness of both mother and child. While the baby’s intestinal tract was originally thought to be free from microbes during pregnancy, this was challenged by a study in 2010 that found bacteria present in the first poo of premature babies, possibly suggesting that the baby’s gut might gather microbes before he or she is born (1). 



On birth the baby’s gut is quickly colonised, with distinct differences between microbiome composition for those who are born via the mother’s birthing canal in comparison to those by caesarean section (C-section). During a traditional delivery, the birthing process pushes the mothers vaginal and faecal microbiota into the baby’s nose and mouth, naturally ‘seeding’ the baby’s gut with a multitude of beneficial microbiota (2). In contrast, a C-section birth results in the first colonisation of the microbiome from the hospital environment. Babies born by C-section are more likely to pick up harmful bugs typically found on the skin and in hospital, such as Staphylococcus and Acinetobacter (1). 

Early differences in gut microbiota composition have been shown to be sustained for up to seven years of age (3). Some observational studies have suggested that C-section babies are more susceptible to allergies, asthma, eczema, and obesity, likely due to this alternative microbiome profile (2, 4). Ultimately however, C-section is a vital operative technique to ensure the best health of mother and child and the best mode of delivery will always be the one most suited to the circumstances of birth.  Practices which have been shown to improve the microbiome composition of C-section babies are; delaying the first bath for more than 12 hours, early skin-to-skin contact with the mother in the first few moments after the birth, and even breastfeeding in the delivery room (5).  

early lıfe

From birth, diet also plays an integral role in developing the composition of the baby’s gut microbiome. Breast fed babies have a distinctly different microbiome profile in comparison to bottle fed babies (6). Those who are breastfed tend to have a larger amount of ‘good’ Bifidobacteria and Lactobacilli in their microbiome due to breast milk containing key prebiotics that feed these beneficial bacteria (7). While infant formulas have added prebiotic oligosaccharides to try and mimic this effect, breast milk still remains the best nutrition for nearly all infants (8). Where possible, it is recommended that babies should be exclusively fed on breastmilk for the first six months for optimal growth, development and health (9). Exclusively breast feeding for this period of time also has benefits for the mother, helping her to lose weight and prevent further pregnancy.  Although breast feeding is recommended, it isn’t always possible or suitable, and is unique to the needs of the mother and baby.    



The gut microbiome is suggested to reach an adult state at around 3 years of age, with Bacteriodetes and Fimicutes as the dominant phyla, making up more than 90% of the total microbial population (10).  Building a diverse gut microbiome has been more commonly associated with health rather than disease, and number of factors have been highlighted that may negatively impact the range of different microbiota in our gut. The hygiene hypothesis, first proposed in 1989, describes how the increasing cleanliness of our environment, due to a shift from ‘rural to urban’ may be behind the increase in chronic diseases due to a lack of beneficial microbes brought into the body from the environment (11). Overuse of antibiotics has also taken its toll, as antibiotics kill off not only the bacteria responsible for the infection but also the bacteria of the gut microbiome. Eating foods containing prebiotic fibre, essential fodder for the gut microbiome, has decreased over the years likely starving our gut microbiota and minimising its chance to flourish.  



Despite a rapid increase in research into this area, the microbial relevance of pregnancy and childhood is poorly understood. While we know that vaginal delivery and breast feeding are preferable, we are not yet in a position to manipulate these interactions for the better. This is mostly due to a lack of understanding around the purpose of each type of bacteria and the specific role each plays in our health. Future strategies may look at tweaking the gut microbiome composition to improve the growth and development of babies and young children, looking to prevent future possible diseases (12).


1.Mshvildadze M, Neu J, Shuster J, Theriaque D, Li N, Mai V. Intestinal microbial ecology in premature infants assessed with non-culture-based techniques. J Pediatr. 2010;156(1):20-5. 

2.Advanced Nutrition and Dietetics in Gastroenterology. Whelan K, editor: John Wiley and Sons Ltd; 2014. 

3.Gronlund MM, Lehtonen OP, Eerola E, Kero P. Fecal microflora in healthy infants born by different methods of delivery: permanent changes in intestinal flora after cesarean delivery. J Pediatr Gastroenterol Nutr. 1999;28(1):19-25. 

4.Bager P, Wohlfahrt J, Westergaard T. Caesarean delivery and risk of atopy and allergic disease: meta-analyses. Clin Exp Allergy. 2008;38(4):634-42. 

5.Patel S. Vaginal seeding: Why we can’t recommend this C-section trend UT Southwestern Medical centre2016 [Available from: 

6.Bezirtzoglou E, Tsiotsias A, Welling GW. Microbiota profile in feces of breast- and formula-fed newborns by using fluorescence in situ hybridization (FISH). Anaerobe. 2011;17(6):478-82. 

7.Coppa GV, Bruni S, Morelli L, Soldi S, Gabrielli O. The first prebiotics in humans: human milk oligosaccharides. J Clin Gastroenterol. 2004;38(6 Suppl):S80-3. 

8.Martin CR, Ling P-R, Blackburn GL. Review of Infant Feeding: Key Features of Breast Milk and Infant Formula. Nutrients. 2016;8(5):279. 

9.Kramer MS KR. Optimal duration of exclusive breastfeeding. Cochrane Database of Systematic Reviews. 2012(8). 

10.van den Elsen LWJ, Poyntz HC, Weyrich LS, Young W, Forbes-Blom EE. Embracing the gut microbiota: the new frontier for inflammatory and infectious diseases. Clinical & Translational Immunology. 2017;6(1):e125. 

11.Strachan DP. Family size, infection and atopy: the first decade of the 'hygiene hypothesis'. Thorax. 2000;55(Suppl 1):S2-S10. 

12.Mueller NT, Bakacs E, Combellick J, Grigoryan Z, Dominguez-Bello MG. The infant microbiome development: mom matters. Trends in molecular medicine. 2015;21(2):109-17. 




Feeding in first year of life Report:

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