ABSTRACT
Aim
To study the relationship between bowel function after birth and at 1–2 years of age in the prospective HELMi cohort of term infants.
Methods
We focused on infants with predominantly green stools (n = 152) for three consecutive weeks in early life and their sex, age, and delivery mode‐matched controls (n = 300), and evaluated bowel function at 1–2 years. We also evaluated bowel function in babies who had cried the most (n = 179) and compared the findings with the rest of the cohort (n = 689).
Results
There were no alarming signs of gastrointestinal dysfunction in any of the infants. Infants with green stools in early life had 1.5–2 times more reports of abdominal symptoms at 1–2 years compared to controls (p < 0.005), and stool‐mucus was twice as frequent at 1 year (p < 0.05). Compared to controls, 1‐year‐old infants who cried most as babies had a higher frequency of defecation (a median of 14 per week [IQR 8–17] vs. 12 [IQR 7–15]; p < 0.05) and showed twice as frequent stool‐mucus at 1 year (p < 0.05).
Conclusion
In healthy term babies, occasional abdominal pain or predominantly green stools were associated with benign gastrointestinal symptoms in later infancy. This functional variation may reflect altered microbiota, warranting further research.
Keywords: birth cohort, defecation, newborn, stool colour, stool consistency
Summary
This study links bowel function in healthy babies to bowel function at 1–2 years of age
Bowel function was reported weekly in babies and reassessed at 1–2 years of age
As the presence of predominantly green stools or frequent crying in infancy was not predictive of major gastrointestinal problems, the findings may reassure parents about benign developmental patterns in infants with normal growth and development.
Abbreviations
- GI
gastrointestinal
- HELMi
Health and Early Life Microbiota Birth Cohort
- IQR
interquartile range
- VAS
visual analogue scales
1. Introduction
Healthy, full‐term infants typically exhibit varying bowel habits and frequent bowel movements, influenced by the type of feeding. Breastfed infants tend to have more frequent and softer stools compared to those who are formula‐fed [1, 2, 3, 4]. Functional gastrointestinal issues are also common in infants and can impact their quality of life [5, 6, 7, 8]. A recent European multicenter study reported that younger age and formula feeding were associated with functional gastrointestinal problems, with regurgitation and constipation being the most frequent symptoms [6], in line with previous reports [9]. The underlying causes for functional gastrointestinal problems are complex and may even involve factors such as domestic violence [6].
Alterations in bowel function and crying patterns are common reasons for seeking medical advice [10, 11]. Recently, we reported bowel function in approximately 1000 infants in a comprehensive birth cohort HELMi, covering up to 17 weeks of age. We utilised reports that the parents completed weekly online, ensuring the timely collection of the data. Surprisingly, 47% of the families reported that for at least 1 week, the infant had stools that were predominantly green in colour, with a similar occurrence in both breast‐fed and formula‐fed infants. Additionally, occasional blood in stools was reported in 9% during this early period. Hard stools were rare [4]. There is limited information on the long‐term gastrointestinal outcomes for healthy infants with green stools, which may be a concern for the parents. In this study, we aimed to investigate the relationship between these patterns in early life and subsequent bowel functions in infants, utilising data from this large, prospective birth cohort [12]. Our focus is on the infants with predominantly green stools in the early months of life and those who experienced excessive initial crying.
2. Materials and Methods
2.1. Study Design and Participants
This study was a nested case–control study from a well‐characterised prospective HELMi (Health and Early Life Microbiota) birth cohort recruited in the Helsinki region, Finland, from February 2016 to March 2018. A detailed description of the HELMi cohort has previously been reported [12]. In brief, the inclusion criteria were singleton, term newborn infants born healthy, with birth weight exceeding 2.5 kg.
In total, 1052 families provided weekly online information on the child's nutrition, bowel function, crying, and health for the first 17 weeks (Table 1). The retention rate of the study was high at the 3‐month mark, with 96.5% (n = 1015) of the participants attending a study visit [13]. Additionally, 99% visited the national well‐baby clinics for follow‐up, including monitoring of weight gain, growth, and development. At 12 weeks (n = 1003), 86% (n = 863) of the infants were exclusively or almost exclusively breastfed (96%–100% of the diet consisting of breast milk), 12% (n = 117) partially formula‐fed, and 2% (n = 21) were exclusively formula‐fed. None of the infants started day care in the first 6 months of life. Infection episodes occurring within the first year of life have previously been reported [14].
TABLE 1.
Baseline characteristics of the HELMi Cohort. a
| No. of infants | 1052 |
|---|---|
| Gestational week (mean) | 40 (1.2 SD) |
| Birth weight, g (mean) | 3559 (437 SD) |
| Sex | Female 49% |
| Mother's age (mean) | 32.8 (4.0 SD) |
| Father's age (mean) | 34.8 (5.1 SD) |
| Caesarean delivery (n) | 176 (17%) |
| No siblings in the household | 49% (514) |
| Exclusive breastfeeding, months (mean) | 3.3 (1.8 SD) |
| Partial breastfeeding, months (mean) | 10.4 (3.3 SD) |
| Maternal education | |
| Secondary school/Upper secondary/vocational school | 11% |
| University including polytechnic | 88% |
| Maternal smoking (yes) | 0.7% |
| Started day care in the first 6 months of life | 0% |
| Vaccinations b | |
| Full program | 77% |
| No vaccinations | 3% |
2.2. Reporting of Gastrointestinal Function
The bowel function of the infants during the first 17 weeks of life was previously published [4]. In brief, parents (mostly mothers) reported bowel function and stool colour of the infants online every week during the first 17 weeks. Parents evaluated typical stool consistency weekly by using the Bristol Stool Form Scale (BSFS), categorising stools into seven types. Low scores indicate firm stool and slow transit, while high scores indicate loose stool and fast transit [15]. The presence of abdominal pain was evaluated with a separate yes/no question. In addition, parents assessed defecation difficulty and abdominal pain using a 100 mm visual analogue scale (VAS) with word anchors at each end. The rightmost position of the scale reflected an uneasy defecation or more pain. The position on the scale was later translated into a number (0–100) that we used in the study. To report the dominant stool colour each week, parents selected the most accurate alternative of six categories (yellow, green, grey, nearly black, light, and dark brown). The presence of blood or mucus in the stools and the occurrence of vomiting were separate yes/no questions [4, 12, 13].
At the ages of 1, 1.5, and 2 years, the parents completed a questionnaire on well‐being and health, including the same items as in early life on abdominal function and defecation patterns during the preceding month [4, 12]. We utilized the responses to these items on bowel function in this follow‐up study.
Bowel function was assessed at 1 year (52–56 weeks), 1.5 years (78–82 weeks), and at 2 years of age (100–104 weeks). Infants with predominantly green stools for at least three consecutive weeks in early life (n = 152) were compared with sex‐, age‐, and delivery‐mode‐matched controls who had predominantly yellow stools and no green stool predominance during the first 17 weeks (n = 300). Additionally, we compared bowel function at one to 2 years of age between infants who cried the most (> 3 h/day at week 5; n = 179) when crying peaked at week 5 in the total cohort and those who cried less (crying 0–2 h/day at week 5; n = 689). The selection of these study groups was previously published [4]. As there was initially more crying in the group with predominantly green stools [4], some infants (n = 39) were included in the analyses of both subgroups.
2.3. Ethics
The study was conducted following the principles of the Helsinki Declaration and the protocol was reviewed by the Ethical Committee of the Helsinki and Uusimaa Hospital District (263/13/03/032015), Finland. All families gave their written informed consent in advance.
2.4. Statistical Analysis
For statistical analyses, we used The GraphPad Prism version 9.0 for Windows and version 10 for Mac (GraphPad Software, San Diego, CA, USA) and the SPSS software program version 29 (IBM Corp., Chicago, IL, USA). The data are presented as a median and interquartile range (IQR) or numbers/proportion (%) when appropriate. Odds Ratios (OR) with 95% confidence intervals (CI) are presented when appropriate, with statistically significant findings. We compared the characteristics between infants using the independent samples t‐test, the Mann–Whitney test, and the Kruskal‐Wallis test as appropriate. Missing data were rare, and according to our assumption, they were random. No corrections were made for missing data. The level of statistical significance was set at p < 0.05.
3. Results
The study adherence was excellent. At the 2‐year follow‐up, 98% of the matched cohort regarding early life stool colour (444 infants), and 90% of the cohort related to crying (780 infants) completed the questionnaire (Figure 1). The overall response rate to questions on abdominal function and defecation patterns at 1–2 years was high, ranging from 83% to 90%. The reported flatulence was not considered in further analyses because the response rate to this item was low (16% at 1 year and 13% at 1.5 years). None of the infants was reported to have a chronic gastrointestinal disease during this follow‐up.
FIGURE 1.
Flowchart of the study population. A few infants (n = 39) initially presenting with predominantly green stools were also included in the stratified crying group.
3.1. Infants With Predominantly Green Stools in Early Life
In infants with predominantly green stools during early life (up to 17 weeks), abdominal symptoms (a single yes/no question) were more frequent at 1 year (p = 0.032, OR 1.678, 95% CI 1.057–2.62), 1.5 years (p = 0.0006, OR 2.513, 95% CI 1.51–4.21), and at 2 years of age (p = 0.034, OR 2.14, 95% CI 1.33–3.66) (Figure 2). Stool mucus was more frequent at 1 year (8.6% (12/140) in the group with green stools compared to 3.1% (9/291) in matched controls, p < 0.05). At 1.5 years, there was no statistical difference between the reports on mucus. Defecation frequency was higher in the group with green stools (median 14 per week, n = 151), compared to the controls (median 12, n = 299), but the difference was not statistically significant. Similarly, there was no difference in reported difficulty of defecation, stool consistency or colour, or presence of abdominal pain in later life (Table S1). Blood in stool was reported in seven infants (1.5% of all respondents; one in the green stool group and six among matched controls).
FIGURE 2.
Abdominal symptoms in infants at the age of 1 year (a), 1.5 years (b), and 2 years (c). Red colour indicates infants who presented with abdominal symptoms, and blue colour indicates infants with no abdominal symptoms. Percentages indicate the proportion of children with abdominal symptoms in each group. The difference between the study groups with predominantly yellow or green stools in early life is statistically significant at each time point (p < 0.05).
3.2. Infants With Excessive Crying in Early Life
Median defecation frequency declined with increasing age. At 1 year, infants with excessive crying in early life had a higher frequency (14 per week, IQR 8–17) compared to controls (12 per week, IQR 7–15). At 1.5 years, the difference was also statistically significant, although medians were comparable (10 per week in both groups). At 2 years, the defecation frequency was similar in both groups (median 9 per week) (Figure 3). Stool mucus was more frequent in infants with excessive crying in early life (6.7%, 12/167) compared to controls (3.2%, 22/667), (p < 0.05) at 1 year of age.
FIGURE 3.
Defecation frequency per week in infants at the age of 1 year, (a) 1.5 years, (b) and 2 years (c). The red colour represents the group of infants with excessive crying in the first months of life, and the yellow colour defines the control group of infants with less crying. The boxes represent the median, and vertical lines the interquartile range.
We observed a minor, though significant, reported difference in the difficulty of defecation. In the group with excessive crying in early life, defecation was less easy at 1 year (median 15, IQR 6–27, compared to 9, IQR 3–21, in controls; p = 0.001) and at 2 years (median 12 compared to 9, p = 0.019). There was no difference in stool consistency or colour, or the presence of abdominal pain (Table S2). The presence of blood in the stool was reported in nine children, all belonging to the control group (1.4%, 9/647 responding). At 1 year, vomiting was reported in 4.7% (8/171) and at 1.5 years, 3.0% (5/165) of the infants with early excessive crying compared to 3.6% and 2.6% of controls (p = 0.051 and p = 0.11), respectively.
4. Discussion
We studied the relationship between early life bowel function in infants up to 17 weeks and that at one to 2 years of age. The study utilised data derived from the HELMi cohort, a comprehensive, prospective birth cohort encompassing approximately 1000 infants [12]. In this cohort, bowel function was monitored using weekly online diaries during the first 17 weeks of life. In prior analyses, we categorised infants based on the predominance of green stools or the presence of excessive daily crying, along with their matched controls [4]. In this study, we followed the subsequent bowel function of infants at 1, 1.5, and 2 years of life, when 98% of the stool colour cohort and 90% of the cohort related to the crying were adherent to the study. Reassuringly, the predominance of green stools or excessive crying was not indicative of major gastrointestinal problems at one to 2 years of age, although some associations with reported bowel function were observed, as discussed below.
Differentiating normal and abnormal bowel function in infants may be challenging in everyday life. Recently, the defecation pattern of healthy children up to 4 years of age was comprehensively reviewed [16], and our findings regarding defecation frequency are consistent with published data. The predominance of green stools in early life is a common phenomenon, indicative of rapid transit of intestinal fluids [4, 17, 18]. This may elicit concern among both parents and healthcare professionals [4], but we did not trace any studies on the follow‐up of bowel function in such infants. Our study included 152 infants who had at least three consecutive weeks of predominantly green stools during their first 4 months of life and compared these with their sex, age, and delivery mode‐matched controls and yellow‐coloured stools. At all points of follow‐up, the reports of abdominal symptoms were more frequent in the cohort of early green stools compared to their matched controls. Additionally, the presence of mucus was reported in 7.9% of the green stool cohort, which was more than twice the rate reported among their matched controls. However, the differences in stool consistency, defecation frequency, and presence of abdominal pain were not statistically different between the groups. In the initial observation period, the frequency of blood in stool was higher within the cohort exhibiting green stools compared to their matched controls. However, by the time the cohort reached 1–2 years of age, this difference had disappeared. Furthermore, the overall prevalence of reports of blood in stool among all participants had decreased from 9.3% [4] to approximately 1.5%. A recent observational cohort of 122 term infants reported bowel function up to 1 year of age and did not report the presence of blood in the stools [8].
The group of infants with excessive crying was identified from the database at the age of 5 weeks, when crying was most abundant and exceeded 3 h/day according to the parental online reports [4]. Thus, the infants were not diagnosed as colicky by healthcare professionals. This group exhibited the most pronounced defecation difficulties in early life, peaking at 6 weeks of age [4]. At both the 1‐ and 2‐year marks, the frequency of reported defecation difficulties was higher in the study group compared to their control group, with less daily crying in early life. Overall, the level of reported defecation difficulties or the intensity of abdominal pain was low. Despite this, the median frequency of defecation was consistently higher in the study group compared to the reference group throughout the follow‐up and exhibited a decrease with increasing age, consistent with the developmental pattern of defecation [19, 20]. Regarding stool consistency, no statistical differences were observed between the two groups. However, the presence of mucus in stools was reported more often in the study group with crying (6.7%) than in their controls (3.2%). There were no significant differences between the crying group and their controls in the other items included in the questionnaire. Likewise, the number of infants with vomiting was comparable (between 3% and 4%). In infant colic, most studies show a link to later functional gastrointestinal problems, probably resulting from shared etiopathogenetic factors (intestinal dysmotility, visceral hypersensitivity, environmental and dietary factors), and symptoms (increased intraluminal gas, irritability). A recent, comprehensive review concluded that a causal relationship between excessive crying and colic and any long‐term consequences remains to be documented [21]. Another recent study followed bowel function in 122 infants born at term for the first year of life; 42% had functional gastrointestinal problems at some point and were more frequently seeking medical advice [8]. Notably, in our study, the symptoms were based on parental reports, and we had no access to medical charts. However, the potential new diagnoses were asked at 3‐month intervals according to the HELMi protocol [12]. Additionally, it has previously been reported that the infants in the HELMi cohort are healthy, and at this age, except for allergies, other chronic health problems were rare [13].
The HELMi cohort has served as a basis for longitudinal studies of infant microbiota in the early years of life [12, 13, 22]. In an earlier study examining stool microbiota in these infants, it was observed that Akkermansia, Bifidobacteria, and Lactobacillus were negatively associated with an increased frequency of defecations during the initial 2 years of life. Conversely, Hemophilus and Klebsiella showed a positive association with more frequent defecations [13]. Although this clinical study does not specifically address this aspect, it would be of interest to link the presently found associations—albeit weak—regarding early life crying and stool colour to the long‐term patterns of microbial development.
The principal strength of our research lies in its prospective study design and the comprehensive collection of detailed diaries documenting the bowel function of infants. Consequently, our data depict ongoing home care, as compared to studies based on medical records or retrospective recall. We also included carefully matched controls, taking into consideration age, sex, and mode of delivery, and stool colour during the initial study period. At 1–2 years of age, most families were adherent to follow‐up questionnaires and thus, the number of infants with data on bowel function was high. As a limitation, we had no access to the medical records of the participants from the ages of 1–2 years. However, none of the participants reported a diagnosis of a chronic gastrointestinal disease [13, 14]. Importantly, the maternal assessment of an infant's health is deemed to correspond closely with the child's actual health condition, as indicated by the presence or absence of health concerns [22]. However, we did not have data on the perceived burden of the infant's symptoms from the parents' perspective.
5. Conclusions
Comprehending the developmental trajectories of bowel function in infants is crucial for providing accurate information and support to families concerned about their infants' defecation patterns, despite normal growth and development. Reassuringly, although there was a minor increase in non‐specific gastrointestinal symptoms in later childhood, the predominance of green stools or frequent crying in early infancy was not predictive of major gastrointestinal problems. Whether this benign functional variation could, in clinical practice, be reflected in alterations in microbiota warrants further research.
Author Contributions
L. Typpö analyzed the data, conducted statistical analyses, and drafted the initial manuscript. T. Solasaari carried out the identification of the infants and mothers, participated in data analyses, and critically revised the manuscript. K. Korpela, Anne Salonen, and WM de Vos conceptualised the HELMi cohort, participated in writing the draft, and critically revised the manuscript. K‐LKolho designed the study and participated in the conceptualization of the HELMi cohort, supervised the data analysis, and critically revised the manuscript. All the authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.
Funding
This work was supported by the Foundation for Paediatric Research, Finland (KLK), the Mary ja Georg C. Ehrnrooth Foundation (grant 202010020 to AS), the Finnish Cultural Foundation (grant 00210976 to AS), and by Tekes/Business Finland (329/31/2015 to WMdV) to establish the HELMi cohort. None of these sources had any role in the design or execution of the research.
Conflicts of Interest
The authors declare no conflicts of interest.
Supporting information
Appendix S1: Supporting Information.
Acknowledgements
We thank the nurses who worked with these children, especially Jaana Valkeapää, along with Heli Suomalainen, Anna Mantere, Eevi Heitto, and Janica Bergström. We also thank Dr. Alise Ponsero and Evgenia Dikareva, MSc, for their contributions to the curation of the questionnaire data. Finally, we thank the participating families for their efforts. Open access publishing facilitated by Helsingin yliopisto, as part of the Wiley ‐ FinELib agreement.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.
References
- 1. Hyams J. S., Treem W. R., Etienne N. L., et al., “Effect of Infant Formula on Stool Characteristics of Young Infants,” Pediatrics 95, no. 1 (1995): 50–54. [PubMed] [Google Scholar]
- 2. Tunc V. T., Camurdan A. D., Ilhan M. N., Sahin F., and Beyazova U., “Factors Associated With Defecation Patterns in 0–24‐Month‐Old Children,” European Journal of Pediatrics 167, no. 12 (2008): 1357–1362. [DOI] [PubMed] [Google Scholar]
- 3. Estorninos E., Lawenko R. B., Palestroque E., Lebumfacil J., Marko M., and Cercamondi C. I., “Infant Formula Containing Bovine Milk‐Derived Oligosaccharides Supports Age‐Appropriate Growth and Improves Stooling Pattern,” Pediatric Research 91, no. 6 (2022): 1485–1492. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4. Solasaari T., Korpela K., Lommi S., et al., “Bowel Function in a Prospective Cohort of 1052 Healthy Term Infants up to 4 Months of Age,” European Journal of Pediatrics 183, no. 8 (2024): 3557–3565. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5. van Tilburg M. A., Hyman P. E., Walker L., et al., “Prevalence of Functional Gastrointestinal Disorders in Infants and Toddlers,” Journal of Pediatrics 166, no. 3 (2015): 684–689. [DOI] [PubMed] [Google Scholar]
- 6. Steutel N. F., Zeevenhooven J., Scarpato E., et al., “Prevalence of Functional Gastrointestinal Disorders in European Infants and Toddlers,” Journal of Pediatrics 221 (2020): 107–114. [DOI] [PubMed] [Google Scholar]
- 7. Velasco‐Benítez C. A., Collazos‐Saa L. I., and García‐Perdomo H. A., “Functional Gastrointestinal Disorders in Neonates and Toddlers According to the Rome IV Criteria: A Systematic Review and Meta‐Analysis,” Pediatrics Gastroenterology Hepatology & Nutrition 25, no. 5 (2022): 376–386. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8. Gatzinsky C., Sillén U., Thornberg S., and Sjöström S., “Bowel Habits in Healthy Infants and the Prevalence of Functional Constipation, Infant Colic and Infant Dyschezia,” Acta Paediatrica 112, no. 6 (2023): 1341–1350. [DOI] [PubMed] [Google Scholar]
- 9. Vandenplas Y., Abkari A., Bellaiche M., et al., “Prevalence and Health Outcomes of Functional Gastrointestinal Symptoms in Infants From Birth to 12 Months of Age,” Journal of Pediatric Gastroenterology and Nutrition 61, no. 5 (2015): 531–537. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10. Benninga M. A., Faure C., Hyman P. E., St James Roberts I., Schechter N. L., and Nurko S., “Childhood Functional Gastrointestinal Disorders: Neonate/Toddler,” Gastroenterology (2016): 15. [DOI] [PubMed] [Google Scholar]
- 11. Yousaf A. and Mutalib M., “Burden of Pediatric Functional Gastrointestinal Disorder in an Emergency Department—A Single‐Center Experience,” Pediatric Emergency Care 38, no. 9 (2022): e1512–e1516. [DOI] [PubMed] [Google Scholar]
- 12. Korpela K., Dikareva E., Hanski E., Kolho K. L., deVos W. M., and Salonen A., “Cohort Profile: Finnish Health and Early Life Microbiota (HELMi) Longitudinal Birth Cohort,” BMJ Open 9, no. 6 (2019): e028500.20. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13. Jokela R., Ponsero A. J., Dikareva E., et al., “Sources of Gut Microbiota Variation in a Large Longitudinal Finnish Infant Cohort,” eBioMedicine 94 (2023): 104695, 10.1016/j.ebiom.2023.104695. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14. Hyvönen S., Tapiainen T., Pokka T., et al., “Perinatal and Other Risk Factors for Common Infections inInfancy: A Prospective Cohort Study,” Pediatric Infectious Disease Journal 42, no. 12 (2023): e447–e453. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15. Russo M., Martinelli M., Sciorio E., et al., “Stool Consistency, but Not Frequency, Correlates With Total Gastrointestinal Transit Time in Children,” Journal of Pediatrics 162, no. 6 (2013): 1188–1192. [DOI] [PubMed] [Google Scholar]
- 16. Baaleman D. F., Wegh C. A. M., de Leeuw T. J. M., et al., “What Are Normal Defecation Patterns in Healthy Children up to Four Years of Age? A Systematic Review and Meta‐Analysis,” Journal of Pediatrics 261 (2023): 113559, 10.1016/j.jpeds.2023.113559. [DOI] [PubMed] [Google Scholar]
- 17. den Hertog J., van Leengoed E., Kolk F., et al., “The Defecation Pattern of Healthy Term Infants up to the Age of 3 Months,” Archives of Disease in Childhood. Fetal and Neonatal Edition 97, no. 6 (2012): F465–F470. [DOI] [PubMed] [Google Scholar]
- 18. Gustin J., Gibb R., Kenneally D., Kutay B., Waimin Siu S., and Roe D., “Characterizing Exclusively Breastfed Infant Stool via a Novel Infant Stool Scale,” Journal of Parenteral and Enteral Nutrition 42, no. 1 (2018): S5–S11, 10.1002/jpen.1468. [DOI] [PubMed] [Google Scholar]
- 19. Munasinghe S., Manathunga S., Hathagoda W., et al., “How Do We Define Normal Bowel Frequency From Newborn to Teens?: A Bayesian Meta‐Analysis,” Journal of Pediatric Gastroenterology and Nutrition 80, no. 4 (2025): 569–579, 10.1002/jpn3.12432. [DOI] [PubMed] [Google Scholar]
- 20. Verkuijl S. J., Trzpis M., and Broens P. M. A., “The Prevalence of Bowel and Bladder Function During Early Childhood: A Population‐Based Study,” Journal of Pediatric Gastroenterology and Nutrition 77, no. 1 (2023): 47–54, 10.1097/MPG.0000000000003804. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21. Indrio F., Dargenio V. N., Francavilla R., Szajewska H., and Vandenplas Y., “Infantile Colic and Long‐Term Outcomes in Childhood: A Narrative Synthesis of the Evidence,” Nutrients 15, no. 3 (2023): 615, 10.3390/nu15030615. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22. Monette S., Seguin L., Gauvin L., and Nikiema B., “Validation of a Measure of Maternal Perception of the Child's Health Status,” Child: Care, Health and Development 33, no. 4 (2007): 472–481. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Appendix S1: Supporting Information.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.