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Gut changes: a baby’s first year

A baby’s gut continues to develop from birth and will do so until they reach early childhood¹. Gastrointestinal (GI) disorders, such as reflux, colic and constipation, are common and can be a result of a baby’s developing gut². Although nothing to worry about, these conditions can cause discomfort for babies and stress to families².

During the first six months of life, infants are particularly prone to GI signs and symptoms that have no obvious structural or bio-mechanical cause¹. The immature GI tract and its associated nervous system and microbiota are not yet functioning at an optimal level². This can cause a range of disorders which, although not classified as organic diseases, can be incredibly distressing for the infant and, of course, concerned parents³`⁴. To learn more on the prevalence and impact of common functional GI disorders, read: ‘The health, wellbeing and financial impact of infant functional gastrointestinal disorders’.

Around 50% of infants will suffer at least one functional GI disorder before six months of age⁵`⁶. The most common one is reflux (which affects around 30% of infants), followed by colic (around 20% of infants) and constipation (around 15%)⁵. It is common for two or more functional GI disorders to coexist in the same infant⁵. Current guidelines provide healthcare professionals with advice to help parents effectively manage these conditions². They highlight the importance of parental reassurance and nutritional advice as the first-line management of functional GI disorders. To learn more about how this management approach can help reduce infants’ distress, improve quality of life for the family, reduce over-prescribing and protect healthcare budgets, read: ‘Optimising the management of functional gastrointestinal disorders in infants — a summary for healthcare professionals’. In the following infographic we look at how a baby’s gut develops during the first 12 months of life:

Our Careline
The information above is designed to help healthcare professionals support parents, but if you still need assistance, at Nutricia Early Life Nutrition we have two carelines with two dedicated phone numbers; one for your patients to call directly, and the other specifically for healthcare professionals. The Nutricia Early Life Nutrition healthcare professional helpline is staffed by people who understand what it’s like to be on the frontline of healthcare. Our team has over a hundred and fifty years’ cumulative experience, including hands-on experience in midwifery, as well as paediatric and neonatal nursing.

Our free healthcare professional helpline is open from 8am to 8pm, Monday to Friday. Just phone 0800 996 1234 for expert advice on infant feeding and nutrition, including common infant feeding problems such as cows’ milk allergy, colic, constipation and reflux.


IMPORTANT NOTICE: Breastfeeding is best for babies. Infant formula is suitable from birth when babies are not breastfed. Follow-on milk is only for babies over 6 months, as part of a mixed diet and should not be used as a breastmilk substitute before 6 months. We advise that all formula milks including the decision to start weaning should be made on the advice of a doctor, midwife, health visitor, public health nurse, dietitian, pharmacist or other professional responsible for maternal and child care. Foods for special medical purposes should only be used under medical supervision. May be suitable for use as the sole source of nutrition for infants from birth, and/or as part of a balanced diet from 6–12 months. Refer to label for details.


  1. Vandenplas Y et al. Gut Health in Early Life: Implications and Management of Gastrointestinal Disorders. Essential Knowledge Briefings. Chichester, England: Wiley; 2015.
  2. Salvatore S et al. Review shows that parental reassurance and nutritional advice help to optimise the management of functional gastrointestinal disorders in infants. Acta Paediatr. 2018. doi:10.1111/apa.14378.
  3. Kurth E et al. Crying babies, tired mothers: what do we know? A systematic review. Midwifery 2011;27(2):187– 94.
  4. Vik T et al. Infantile colic, prolonged crying and maternal postnatal depression. Acta Paediatr 2009; 98(8):1344–8.
  5. Vandenplas Y et al. Prevalence and Health Outcomes of Functional Gastrointestinal Symptoms in Infants From Birth to 12 Months of Age. J Pediatr Gastroenterol Nutr. 2015;61(5):531–537.
  6. Iacono G et al. Gastrointestinal symptoms in infancy: a population-based prospective study. Dig Liver Dis 2005;37(6):432–8.
  7. The National Institute for Health and Care Excellence (NICE). Clinical Knowledge Summaries: Colic — infantile. Available at: https://cks.nice.org.uk/colic-infantile[Accessed May 2018].
  8. Pijpers MA et al. Functional constipation in children: a systematic review on prognosis and predictive factors. J Pediatr Gastroenterol Nutr. 2010;50(3):256–268.
  9. Van den Berg MM et al. Epidemiology of childhood constipation: a systematic review. Am J Gastroenterol. 2006;101(10):2401–2409.
  10. The National Institute for Health and Care Excellence (NICE). Clinical Knowledge Summaries: GORD in children. Available at: https://cks.nice.org.uk/gord-in-children. [Accessed May 2018].
  11. Weaver LT et al. Small intestinal length: a factor essential for gut adaptation. Gut. 1991;32(11):1321–1323.
  12. Arrieta MC et al. The intestinal microbiome in early life: health and disease. Front Immunol. 2014;5:427.
  13. Nash MJ et al. Early Microbes Modify Immune System Development and Metabolic Homeostasis-The “Restaurant” Hypothesis Revisited. Front Endocrinol. 2017;8:349.