Managing with colic & constipation in early infancy

Traditionally, colic was defined by Wessel’s criteria (three hours a day, three days a week, for three weeks). However, NICE CKS (2025), recognises colic as a spectrum of recurrent and prolonged periods of infant crying that occurs for no apparent reason.

The precise cause remains poorly understood, however some research suggests that infants with colic often have an imbalance in the gut microbiome, in particular low counts of beneficial Lactobacillus (Savino et al., 2009). An additional factor is partial lactose digestion, where relative lactase deficiency leads to colonic fermentation and gaseous distention (Kanabar et al., 2001). Having a developed understanding of the anatomical maturity of the infant gut is beneficial to undertaking effective clinical assessments regarding colic.

The rate of gastric emptying is a considerable factor in digestive distress.

Comfort formulas tend to use 100% whey protein that has been partially hydrolysed. This pre-digestion process ensures that the protein chains are smaller, lessening the time the milk spends in the stomach and potentially reducing the discomfort that contributes to evening crying (Wu et al., 2017). The first few weeks of a baby’s life are a crucial time for the colonisation of the gut (Houghteling & Walker, 2015; Turroni et al., 2020).Healthcare professionals understand that early feeding choices dictate the first, and most important, types of bacteria for infant development.

Breast milk contains Human Milk Oligosaccharides (HMOs), which drive the growth of Bifidobacterium (Kiely et al., 2023; Ruiz-Moyano et al., 2013).These bacteria make short chain fatty acids (SCFAs) that lower colonic pH, inhibiting pathogens. If parents choose not to breastfeed their babies and instead use infant formula, their infants may experience a higher pH gut, associated with harder stools (Eor et al., 2023). Specialised formulas often include probiotics such as Galacto-oligosaccharides (GOS) to bridge this gap.

Preliminary data suggests that the "colic cry" may be a neurological response to distension of the gut (Nocerino et al., 2015; Salvatore et al., 2021). The enteric nervous system communicates directly with the central nervous system via the vagus nerve (Giuffrè et al., 2020; Ullah et al., 2023). For some babies, a heightened sensitivity to internal stimuli exists.In these infants, normal physiological processes such as the digestive clear out reflex, are perceived as painful. This can explain why cortisol-lowering, soothing strategies like skin to skin work so well.

One of the most critical roles for clinicians is the ability to distinguish between functional colic and CMPA, a distinction that could fundamentally change an infant's treatment path. An incorrect diagnosis can lead to unnecessary management with amino acid formulas or extensively hydrolysed formulas (EHF).

The real tell-tale difference is that while colic mostly causes localised distress, CMPA tends to have much more of a systemic effect. The CMPA red flags to look out for include: Atopic eczema or urticaria, chronic coughing or wheezing, persistent vomiting, chronic diarrhoea, blood in the stool or failure to thrive.

The clinical management of an infant's digestive issues is as much about the parents' psychological health as it is about the infant's gut. There is often a visible threshold of exhaustion. When parents hit that wall, there is an inevitable cascade of medical intervention that might have been avoided with earlier, holistic support.

Studies show a direct link between relentless infant crying and a spike in Edinburgh Postnatal Depression Scale scores. When a baby just won't stop crying, parents often lose confidence in their own abilities. That sudden dip in parental self-efficacy is often the tipping point that leads them to give up on breastfeeding much sooner than they had planned. (Miller, Barr and Eaton, 2013) and (Vik et al., 2009)

While it’s true that formula fed babies naturally have firmer stools, parents often worry that this is constipation, when in fact there’s no underlying medical issue. It is only considered true constipation, the kind that needs medical intervention, when the baby is passing hard stools and showing clear signs of distress.

NICE CG99 (2025) states that dietary adjustments alone aren’t enough to soften hard faeces. In contrast, HSE (2025) guidance prioritises checking the powder to water ratio.

To provide a clear pathway for primary care, the following algorithm integrates NICE CKSand BSPGHAN guidance:

Firstly, rule out surgical or organic causes (e.g., green vomit, distended abdomen, blood in stool). Parents should next be shown strategies for encouraging responsive feeding and soothing strategies, such as motion and white noise. Next, is to review a feed (are they sucking in air?) and preparation technique. If symptoms persist, it is suggested to trial simeticone or lactase drops for one week only. Guidance states to stop if there is no improvement. Lastly, is to consider a 2 week trial of a Comfort formula with partially hydrolysed protein and reduced lactose. Underpinning the success of any intervention is to review outcomes. If successful, this approach can be continued until weaning.

The BSPGHAN/ESPGHAN (2024) position paper highlights that while specialised formulas may reduce symptoms, they should not replace the goal of supporting breastfeeding. Moving to Comfort formulas should only be considered as a viable option if symptoms continue to cause distress after first line techniques are exhausted.

The primary obligation as clinicians is to provide parents with accurate, factual data, demonstrating that infant safety and compassionate care are at the core of professional accountability and clinical integrity.