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Unsettled and Crying Babies

Excessive crying and unsettled behaviour are acknowledged as some of the most common reasons for primary care visits in early in life.

Colic affects approximately 5–25% of infants, with symptoms typically peaking between 6-8 weeks and resolving by 3-4 months. Infant colic is defined via the Rome IV criteria as recurrent and prolonged periods of crying, fussing or irritability in infants under 5 months of age, without identifiable cause and in the absence of failure to thrive, fever or illness.1

Whilst in most cases, colic is is benign and self-limiting, there is a need for careful history and examination to exclude red flags (poor weight gain, fever, bilious vomiting, blood in stool, lethargy), ensure a thorough assessment of feeding adequacy and growth, and to provide reassurance and parental support.2

Aetiology

Although the pathophysiology remains multifactorial and is not clearly understood, proposed mechanisms include gastrointestinal immaturity, altered gut microbiota, visceral hypersensitivity and gut-brain signalling pathways.1,10

Management

In most cases, symptoms resolve without medical intervention. Reassurance and parental support remain first-line.2,10

Probiotics

Systematic reviews and meta-analyses report reduced crying duration in breastfed infants receiving Lactobacillus reuteri DSM 17938 compared with placebo.3-6 Evidence in formula-fed infants is less consistent.4

Bifidobacterium animalis subsp. lactis (BB-12®) has also been evaluated in randomised controlled trials in breastfed infants with colic. In double-blind, placebo-controlled studies, BB-12® supplementation was associated with reductions in crying duration and fussing compared with placebo over the intervention period.7,8

Overall, probiotic effects appear strain-specific and population-dependent, and findings should be interpreted within the context of study design, feeding type and baseline symptom severity.3-6

Maternal dietary modification

In breastfed infants, limited evidence supports a trial of maternal low-allergen diet in selected cases, although findings are variable.5,6,10

Formula considerations

Position papers and systematic reviews note inconsistent evidence supporting routine use of partially hydrolysed, reduced lactose or supplemented formulas for colic in otherwise healthy infants.5,9

A recent randomised controlled trial in mixed-fed infants compared formula made with milk free of A1-type β-casein and conventional formula. Lower mean gastrointestinal symptom scores and fewer reported crying episodes were observed in the A1-free group over the study period.11

These findings contribute to the evolving literature regarding feeding tolerance. Further independent studies are warranted.

References

  1. Benninga MA, Nurko S, Faure C, Hyman PE, Roberts ISJ, Schechter NL. Childhood functional gastrointestinal disorders: neonate/toddler. Gastroenterology. 2016;150(6):1443–1455. doi:10.1053/j.gastro.2016.02.016
  2. Royal Children’s Hospital Melbourne. Clinical practice guideline: Unsettled or crying babies [Internet]. Melbourne: The Royal Children’s Hospital; [cited 2026 Feb 27]. Available from: https://www.rch.org.au/clinicalguide/guideline_index/crying_baby_infant_distress/
  3. Sung V, D’Amico F, Cabana MD, Chau K, Koren G, Savino F, et al. Lactobacillus reuteri to treat infant colic: a meta-analysis. Pediatrics. 2018;141(1):e20171811. doi:10.1542/peds.2017-1811
  4. Ong TG, Gordon M, Banks SS, Thomas MR, Akobeng AK. Probiotics to prevent infantile colic. Cochrane Database Syst Rev. 2019;(3):CD012473. doi:10.1002/14651858.CD012473.pub2
  5. Hjern A, Lindblom K, Reuter A, Silfverdal SA. A systematic review of prevention and treatment of infantile colic. Acta Paediatr. 2020;109(9):1733–1744. doi:10.1111/apa.15247
  6. Simonson J, Hall R, Miller S. Probiotics for the management of infantile colic: a systematic review. MCN Am J Matern Child Nurs. 2021;46(2):88–96. doi:10.1097/NMC.0000000000000691
  7. Nocerino R, De Filippis F, Cecere G, Marino A, Micillo M, Di Scala C, et al. The therapeutic efficacy of Bifidobacterium animalis subsp. lactis BB-12® in infant colic: a randomised, double-blind, placebo-controlled trial. Aliment Pharmacol Ther. 2020;51(1):110–120. doi:10.1111/apt.15561
  8. Chen K, Zhang G, Xie H, You L, Li H, Zhang Y, et al. Efficacy of Bifidobacterium animalis subsp. lactis BB-12® on infant colic: a randomised, double-blind, placebo-controlled study. Benef Microbes. 2021;12(6):531–540. doi:10.3920/BM2020.0233
  9. Haiden N, et al. Infant formulas for the treatment of functional gastrointestinal disorders (regurgitation, colic, constipation): a position paper of the ESPGHAN Nutrition Committee. J Pediatr Gastroenterol Nutr. 2024;79(1):168–180. doi:10.1002/jpn3.12240
  10. Rishanghan L, Hinds R. An overview of the management of functional gastrointestinal disorders in infancy. Gastrointest Disord. 2023;5(4):500–507. doi:10.3390/gidisord5040041
  11. Li J, Yang T, Sheng X. Effect of infant formula made with milk free of A1-type β-casein on growth and comfort: a randomized controlled trial. Food Sci Nutr. 2025;13:e70606. doi:10.1002/fsn3.70606