Abstract
Background
Anorexia nervosa has potential to influence the development and function of the gastrointestinal system. We assessed the association between maternal anorexia nervosa and risk of gastrointestinal morbidity in offspring.
Methods
We analyzed a longitudinal cohort of 1,269,370 children born in Quebec, Canada, between 2006 and 2022. The exposure was maternal anorexia nervosa. The outcome was hospitalization for pediatric gastrointestinal disorders, including hypertrophic pyloric stenosis, inflammatory bowel disease, and other digestive morbidity. Follow-up ranged from 1 to 17 years. We used adjusted Cox regression models to obtain hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between maternal anorexia nervosa and pediatric gastrointestinal disorders.
Results
A total of 2,447 children (0.2%) had a mother with anorexia nervosa. By age 17 years, the cumulative incidence of gastrointestinal disorders was higher among children whose mothers had anorexia nervosa than other children (165.7 vs. 129.4 per 1,000). Compared with no anorexia, maternal anorexia nervosa was associated with a greater risk of any childhood gastrointestinal disorder (HR: 1.42, 95% CI: 1.26–1.61), particularly hypertrophic pyloric stenosis (HR: 2.51, 95% CI: 1.35–4.66), inflammatory bowel disease (HR: 2.46, 95% CI: 1.67–3.64), and rectal hemorrhage (HR: 3.46, 95% CI: 1.97–6.09). Children whose mothers developed anorexia nervosa after age 20 years or were hospitalized more than once for anorexia had the greatest risk of gastrointestinal morbidity. The associations were not explained by digestive birth defects.
Conclusion
Maternal anorexia nervosa is associated with pediatric gastrointestinal disorders that could potentially be mitigated with psychosocial support, nutritional rehabilitation, and breastfeeding.
Keywords: anorexia nervosa, child, constipation, digestive system diseases, hypertrophic pyloric stenosis, malnutrition
Introduction
Gastrointestinal morbidity is common in childhood and adolescence, affecting up to a quarter of patients between birth and age 18 years (Robin et al., 2018). While many factors contribute, a growing body of evidence suggests that maternal mental illness may be a risk factor for digestive morbidity in children (Davidsen et al., 2022; Heuckendorff et al., 2022; Le-Nguyen, Piché, Lee, & Auger, 2021). However, the relationship between maternal anorexia nervosa and pediatric gastrointestinal morbidity has received limited attention. Anorexia nervosa is prevalent in women of reproductive age (Smink, van Hoeken, & Hoek, 2012), and can lead to weight loss and malnutrition severe enough to affect fetal development (Hoffman, Zerwas, & Bulik, 2011). Anorexia nervosa is associated with inflammatory bowel disease and celiac disease (Wotton, James, & Goldacre, 2016), conditions with a genetic component that may be transmitted to children (Bonfils et al., 2025; Emilsson, Magnus, & Størdal, 2015). Mothers with anorexia nervosa also tend to breastfeed less (Torgersen et al., 2010), which may amplify the risk of gastrointestinal morbidity in childhood (Rebhan et al., 2009; Xu et al., 2017).
Although the association with gastrointestinal morbidity is unclear, data are beginning to suggest that maternal anorexia nervosa is linked with other health outcomes in offspring (Dobrescu et al., 2024; Nilsson, Ozsvar, Gissler, & Lavebratt, 2024). A longitudinal cohort study of 649,956 children from Finland found that maternal anorexia nervosa was associated with an increased risk of mood, anxiety, and neurodevelopmental disorders in children before age 17 years (Nilsson et al., 2024). Prospective analyses from Sweden have found that offspring of mothers with anorexia nervosa are more likely to develop endocrine, immune, and metabolic disorders (Dobrescu et al., 2024). Some of these disorders may cluster with inflammatory bowel disease, hepatobiliary morbidity, or other pediatric digestive conditions. Yet, the possibility that maternal anorexia nervosa could be linked with digestive disorders in childhood has not been considered. We assessed the association between maternal anorexia nervosa and pediatric gastrointestinal morbidity in a large cohort of children from Canada. We hypothesized that children whose mothers had anorexia nervosa would be more likely to have gastrointestinal morbidity.
Materials and methods
Study design and population
We carried out a longitudinal cohort study of 1,269,370 children born in hospitals within Quebec, Canada, between April 2006 and March 2022. The cohort was drawn from the Maintenance and Use of Data for the Study of Hospital Clientele registry, which comprises discharge abstracts for all admissions in the province. The population of Quebec is ethnically diverse, with 16% of residents from visible minorities (Quebec Statistics Institute, 2024). In Quebec, most children are born in a hospital and are admitted (Auger et al., 2022). Data from prenatal ambulatory care charts are included in the registry, with information entered by medical archivists following standardized coding algorithms (Ministry of Health and Social Services, 2023). Each child is linked with their mother and assigned a unique identifier, which is used to track all hospitalizations after birth up until March 2023. We included children who survived birth. The sample excludes 7,252 children (0.5%) who did not have maternal data.
Anorexia nervosa
The exposure was maternal anorexia nervosa requiring inpatient treatment or prenatal ambulatory care anytime during the study. Maternal information on anorexia nervosa was available starting from 1989. We identified mothers with anorexia nervosa using diagnostic codes from the 9th and 10th revisions of the International Classification of Diseases (ICD-9 307.1/ICD-10 F50.0, F50.1). The ICD follows the Diagnostic and Statistical Manual of Mental Disorders coding system (Birgegård et al., 2022).
We examined the characteristics of mothers with anorexia nervosa, including the timing of the first admission (before pregnancy, during pregnancy, and after birth of the child), age at first hospitalization (8–14, 15–19, and ≥20 years), length of stay at first admission (<30 and ≥30 days), and total number of hospitalizations (1 and ≥2 admissions).
Pediatric gastrointestinal outcomes
The main outcome was hospitalization for gastrointestinal disorders during childhood. We considered the following pediatric gastrointestinal morbidities: inflammatory bowel disease, gastritis, hepatobiliary diseases, appendicitis, gastroenteritis, gastroesophageal reflux disease, hernia, congenital hypertrophic pyloric stenosis, other digestive defects (Hirschsprung’s disease, Meckel’s diverticulum, biliary or intestinal atresia, and other anomalies of the tongue, mouth, pharynx, esophagus, gallbladder, intestines, bile ducts, liver, or pancreas), intestinal obstruction, intestinal malabsorption, rectal hemorrhage, constipation, and dental caries. We used diagnostic codes to identify children with these disorders (Supplementary Table S1). We could not include benign or functional gastrointestinal disorders that did not require hospitalization.
Covariates
Potential confounders included maternal age at birth (<25, 25–34, and ≥35 years), maternal parity (0, 1, and ≥2 previous deliveries), child sex (male and female), multiple birth (yes and no), maternal metabolic disorders (hypertension, type 1 and 2 diabetes, obesity, and dyslipidemia, expressed as a binary variable), maternal digestive disorders (esophagitis, gastritis, duodenitis, noninfective enterocolitis, celiac disease, and hepatobiliary disorders, also expressed as a binary variable), socioeconomic position (advantaged, middle, disadvantaged, and unknown), rural residence (yes, no, and unknown), and year of birth (2006–2010, 2011–2016, and 2017–2022). Socioeconomic advantage and disadvantage included individuals residing in the least and most deprived fifth of neighborhoods according to a population-based index of average income, education level, and unemployment rates (Pampalon, Hamel, Gamache, Simpson, & Philibert, 2014).
Data analysis
We assessed characteristics at birth and the cumulative incidence of hospitalization for gastrointestinal disorders at age 17 years, as well as hospitalization rates per 10,000 person-years. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between maternal anorexia nervosa and offspring gastrointestinal disorders using Cox proportional hazards regression models adjusted for maternal age, maternal parity, child sex, multiple birth, maternal metabolic or digestive disorders, socioeconomic position, rural residence, and year of birth. We verified the proportionality of hazards with log(−log survival) curves, and defined the time scale as the number of days between birth and first hospitalization for a gastrointestinal disorder, death, or study end (March 31, 2023). We censored children who died during follow-up or who were never admitted for a gastrointestinal disorder during childhood, and used robust sandwich estimators to account for siblings with the same mother.
We examined how the timing, age, length of stay, and total number of maternal anorexia nervosa admissions affected the risk of pediatric gastrointestinal hospitalization. We also examined associations at different ages using flexible parametric survival models (Dewar & Khan, 2015). In sensitivity analyses, we excluded children with congenital digestive defects to ensure that anomalies did not explain the association between anorexia nervosa and childhood gastrointestinal disorders, and assessed associations according to socioeconomic strata.
We conducted statistical analyses in SAS v9.4 (SAS Institute Inc., Cary, NC). The University of Montreal Hospital Centre review board issued an ethics waiver, as the data were anonymized and informed consent was not required.
Results
Among 1,269,370 children born between 2006 and 2022, 2,447 (0.2%) had a mother with anorexia nervosa (Table 1). Mothers with anorexia nervosa were more likely to be under age 35 years, have multiple births or a comorbid digestive disorder, and be socioeconomically advantaged than mothers without anorexia nervosa.
Table 1.
Baseline characteristics of children exposed to maternal anorexia nervosa
| No. children (%) | ||
|---|---|---|
| Maternal anorexia nervosa | No maternal anorexia nervosa | |
| Maternal age at birth, years | ||
| <25 | 399 (16.3) | 184,693 (14.6) |
| 25–34 | 1,698 (69.4) | 842,259 (66.5) |
| ≥35 | 350 (14.3) | 239,971 (18.9) |
| Maternal parity | ||
| 0 | 1,204 (49.2) | 618,059 (48.8) |
| 1 | 803 (32.8) | 438,911 (34.6) |
| ≥2 | 440 (18.0) | 209,953 (16.6) |
| Child sex | ||
| Male | 1,254 (51.2) | 650,610 (51.4) |
| Female | 1,193 (48.8) | 616,313 (48.6) |
| Multiple birth | ||
| Yes | 79 (3.2) | 27,233 (2.1) |
| No | 2,368 (96.8) | 1,239,690 (97.9) |
| Maternal metabolic disorder a | ||
| Yes | 132 (5.4) | 80,143 (6.3) |
| No | 2,315 (94.6) | 1,186,780 (93.7) |
| Maternal digestive disorder b | ||
| Yes | 32 (1.3) | 10,638 (0.8) |
| No | 2,415 (98.7) | 1,256,285 (99.2) |
| Socioeconomic position | ||
| Advantaged | 507 (20.7) | 220,728 (17.4) |
| Middle | 1,485 (60.7) | 737,566 (58.2) |
| Disadvantaged | 349 (14.3) | 255,257 (20.1) |
| Rural residence | ||
| Yes | 449 (18.3) | 231,268 (18.3) |
| No | 1,960 (80.1) | 1,013,787 (80.0) |
| Year of birth | ||
| 2006–2010 | 622 (25.4) | 368,467 (29.1) |
| 2011–2016 | 980 (40.0) | 484,653 (38.3) |
| 2017–2022 | 845 (34.5) | 413,803 (32.7) |
| Total | 2,447 (100.0) | 1,266,923 (100.0) |
Hypertension, diabetes (types 1 and 2), obesity, and dyslipidemia.
Esophagitis, gastritis, duodenitis, noninfective enterocolitis, celiac disease, and hepatobiliary disorders.
Children who had mothers with anorexia nervosa were more frequently hospitalized for gastrointestinal disorders (Figure 1). At age 2 years, the cumulative rate of hospitalization was 72.4 for every 1,000 children whose mothers had anorexia nervosa, compared with 45.2 for children with unaffected mothers. At age 17 years, the cumulative rate was 165.7 for every 1,000 children whose mothers had anorexia nervosa, compared with 129.4 for children with unaffected mothers.
Figure 1.
Cumulative incidence of hospitalization for pediatric gastrointestinal disorders up to age 17 years.
Children who had mothers with anorexia nervosa were more likely to have gastrointestinal disorders in adjusted regression models (Table 2). Compared with no anorexia nervosa, maternal anorexia nervosa was associated with 1.42 times the risk of any admission for a gastrointestinal disorder during childhood (95% CI: 1.26–1.61). Children whose mothers were first admitted for anorexia nervosa before pregnancy (HR: 1.42, 95% CI: 1.24–1.62) or for <30 days (HR: 1.57, 95% CI: 1.36–1.82) had a particularly elevated risk of hospitalization for gastrointestinal morbidity. Children whose mothers were treated for anorexia nervosa after age 20 years (HR: 1.69, 95% CI: 1.36–2.10) or had two or more admissions for anorexia nervosa (HR: 1.61, 95% CI: 1.32–1.96) were also at risk.
Table 2.
Maternal anorexia nervosa and risk of childhood hospitalization for gastrointestinal morbidity
| Total no. children | No. events | Rate per 10,000 person-years | Hazard ratio (95% CI) | ||
|---|---|---|---|---|---|
| Unadjusted | Adjusted a | ||||
| Maternal anorexia nervosa | |||||
| Yes | 2,447 | 303 | 160.8 | 1.43 (1.26–1.61) | 1.42 (1.26–1.61) |
| No | 1,266,923 | 115,239 | 109.8 | Reference | Reference |
| Timing of first maternal anorexia nervosa admission | |||||
| Before pregnancy | 2,108 | 253 | 158.5 | 1.39 (1.22–1.59) | 1.42 (1.24–1.62) |
| During pregnancy | 126 | 15 | 192.5 | 1.57 (0.95–2.58) | 1.61 (0.97–2.67) |
| After birth | 213 | 35 | 166.5 | 1.67 (1.14–2.43) | 1.40 (0.95–2.04) |
| No anorexia nervosa | 1,266,923 | 115,239 | 109.8 | Reference | Reference |
| Age at first maternal anorexia nervosa admission, years | |||||
| 8–14 | 572 | 63 | 159.6 | 1.35 (1.03–1.76) | 1.39 (1.06–1.82) |
| 15–19 | 1,218 | 134 | 143.6 | 1.26 (1.06–1.51) | 1.28 (1.08–1.53) |
| ≥20 | 657 | 106 | 190.3 | 1.77 (1.42–2.20) | 1.69 (1.36–2.10) |
| No anorexia nervosa | 1,266,923 | 115,239 | 109.8 | Reference | Reference |
| Length of stay at first maternal anorexia nervosa admission, days | |||||
| <30 | 1,507 | 212 | 180.5 | 1.63 (1.40–1.88) | 1.57 (1.36–1.82) |
| ≥30 | 940 | 91 | 128.1 | 1.12 (0.90–1.40) | 1.17 (0.94–1.46) |
| No anorexia nervosa | 1,266,923 | 115,239 | 109.8 | Reference | Reference |
| No. maternal anorexia nervosa admissions | |||||
| 1 | 1,565 | 181 | 148.5 | 1.32 (1.13–1.55) | 1.32 (1.13–1.55) |
| ≥2 | 882 | 122 | 183.3 | 1.62 (1.33–1.98) | 1.61 (1.32–1.96) |
| No anorexia nervosa | 1,266,923 | 115,239 | 109.8 | Reference | Reference |
Adjusted for maternal age, maternal parity, child sex, multiple birth, maternal metabolic disorders, maternal digestive disorders, socioeconomic position, rural residence, and year of birth.
Maternal anorexia nervosa was strongly associated with several gastrointestinal morbidities (Table 3). Compared with no anorexia nervosa, children who had mothers with anorexia nervosa were more likely to be hospitalized for hypertrophic pyloric stenosis (HR: 2.51, 95% CI: 1.35–4.66), gastritis (HR: 2.48, 95% CI: 1.41–4.36), inflammatory bowel disease (HR: 2.46, 95% CI: 1.67–3.64), intestinal malabsorption (HR: 2.17, 95% CI: 1.59–2.97), rectal hemorrhage (HR: 3.46, 95% CI: 1.97–6.09), and constipation (HR: 2.02, 95% CI: 1.45–2.83). Associations were also present with gastroesophageal reflux disease and gastroenteritis. Maternal anorexia nervosa was not associated with pediatric hernias, intestinal obstruction, appendicitis, hepatobiliary disease, and dental caries.
Table 3.
Maternal anorexia nervosa and risk of childhood hospitalization for specific gastrointestinal disorders
| Maternal anorexia nervosa | No maternal anorexia nervosa | Hazard ratio (95% CI) | ||||
|---|---|---|---|---|---|---|
| No. children | Rate per 10,000 person-years (95% CI) | No. children | Rate per 10,000 person-years (95% CI) | Unadjusted | Adjusted a | |
| Inflammatory bowel disease | 27 | 13.0 (8.9–18.9) | 5,992 | 5.3 (5.2–5.4) | 2.39 (1.62–3.54) | 2.46 (1.67–3.64) |
| Gastritis | 12 | 5.7 (3.2–10.1) | 2,669 | 2.4 (2.3–2.4) | 2.42 (1.38–4.27) | 2.48 (1.41–4.36) |
| Hepatobiliary disease | 8 | 3.8 (1.9–7.6) | 3,601 | 3.2 (3.1–3.3) | 1.19 (0.59–2.37) | 1.18 (0.59–2.36) |
| Appendicitis | 13 | 6.2 (3.6–10.6) | 9,058 | 8.0 (7.8–8.2) | 0.80 (0.47–1.38) | 0.80 (0.46–1.38) |
| Gastroenteritis | 83 | 40.8 (32.9–50.6) | 28,152 | 25.4 (25.1–25.7) | 1.56 (1.25–1.95) | 1.57 (1.25–1.97) |
| Gastroesophageal reflux disease | 82 | 40.0 (32.3–49.7) | 21,050 | 18.8 (18.6–19.1) | 2.04 (1.61–2.59) | 1.98 (1.56–2.51) |
| Hernia | 30 | 14.4 (10.1–20.6) | 15,353 | 13.7 (13.5–13.9) | 1.03 (0.71–1.48) | 1.03 (0.71–1.48) |
| Hypertrophic pyloric stenosis | 10 | 4.8 (2.6–8.8) | 2,033 | 1.8 (1.7–1.9) | 2.55 (1.37–4.74) | 2.51 (1.35–4.66) |
| Other digestive defect b | 15 | 7.1 (4.3–11.9) | 5,967 | 5.3 (5.2–5.4) | 1.31 (0.79–2.17) | 1.31 (0.79–2.16) |
| Intestinal obstruction | 7 | 3.3 (1.6–7.0) | 3,127 | 2.8 (2.7–2.9) | 1.18 (0.56–2.48) | 1.17 (0.56–2.44) |
| Intestinal malabsorption | 42 | 20.2 (15.0–27.4) | 9,907 | 8.8 (8.6–9.0) | 2.23 (1.63–3.05) | 2.17 (1.59–2.97) |
| Rectal hemorrhage | 12 | 5.7 (3.2–10.1) | 1,794 | 1.6 (1.5–1.7) | 3.53 (2.00–6.22) | 3.46 (1.97–6.09) |
| Constipation | 36 | 17.3 (12.5–24.0) | 9,397 | 8.3 (8.2–8.5) | 2.05 (1.46–2.86) | 2.02 (1.45–2.83) |
| Dental caries | 41 | 19.6 (14.5–26.7) | 25,946 | 23.2 (22.9–23.5) | 0.84 (0.60–1.18) | 0.86 (0.61–1.20) |
Hazard ratio for maternal anorexia nervosa versus no anorexia, adjusted for maternal age, maternal parity, child sex, multiple birth, maternal metabolic disorders, maternal digestive disorders, socioeconomic position, rural residence, and year of birth.
Hirschsprung’s disease, Meckel’s diverticulum, biliary or intestinal atresia, and other anomalies of the tongue, mouth, pharynx, esophagus, gallbladder, intestines, bile ducts, liver, or pancreas.
Anorexia nervosa was particularly associated with gastrointestinal morbidity the first year of life (Figure 2). At age 1 year, maternal anorexia nervosa was associated with 1.68 times the risk of hospitalization for gastroenteritis (95% CI: 1.31–2.16) and 2.63 times the risk of hospitalization for intestinal malabsorption (95% CI: 1.56–4.44). These risks decreased over time and became closer to the null starting around age 4 years for gastroenteritis and 2.5 years for intestinal malabsorption. In contrast, risk of hospitalization for inflammatory bowel disease peaked at age 2 years (HR: 2.66, 95% CI: 1.56–4.56) before gradually decreasing to become no different from the null at around age 10 years.
Figure 2.
Maternal anorexia nervosa and risk of childhood gastrointestinal hospitalization over time.
Hazard ratio (solid black line) for maternal anorexia nervosa versus no anorexia, adjusted for maternal age, maternal parity, child sex, multiple birth, maternal metabolic disorders, maternal digestive disorders, socioeconomic position, rural residence, and year of birth. Dotted black lines correspond to upper and lower 95% confidence limits. Horizontal gray line represents a hazard ratio of 1 (null association).
In sensitivity analyses, maternal anorexia nervosa remained associated with pediatric gastrointestinal disorders after excluding children with congenital digestive defects (Supplementary Table S2). Compared with no anorexia nervosa, disadvantaged children whose mothers had anorexia nervosa were more likely to be hospitalized for gastrointestinal disorders (HR: 1.64, 95% CI: 1.24–2.15), while advantaged children did not appear to be as affected (HR: 1.18, 95% CI: 0.89–1.59).
Discussion
In this study of more than 1.2 million children followed up to age 17 years, children who had mothers with anorexia nervosa were 40% more likely to have gastrointestinal morbidity compared with other children. Certain maternal characteristics were associated with greater risks, especially maternal anorexia nervosa requiring hospital treatment before pregnancy or after age 20 years. Mothers with potentially severe anorexia nervosa, as reflected by multiple admissions or hospital stays that were too short, were also more likely to have children with a greater risk of gastrointestinal morbidity. Maternal anorexia nervosa was associated with a range of pediatric gastrointestinal symptoms and disorders, including hypertrophic pyloric stenosis, inflammatory bowel disease, gastritis, intestinal malabsorption, rectal hemorrhage, and constipation. The findings suggest that offspring of mothers with anorexia nervosa have an elevated risk of gastrointestinal morbidity during childhood and adolescence.
Up to 4% of women of reproductive age have anorexia nervosa (Smink et al., 2012). Anorexia nervosa is characterized by severe weight loss and food restriction due to body image distortion and fear of weight gain (Zipfel, Giel, Bulik, Hay, & Schmidt, 2015). While anorexia nervosa is considered a mental health disorder, patients are known to be at risk of digestive complications such as gastroparesis, superior mesenteric artery syndrome, and hepatitis (Mehler & Brown, 2015). Some data suggest that patients with anorexia nervosa are more likely to have preexisting autoimmune disorders of the gastrointestinal tract, including inflammatory bowel disease and celiac disease (Wotton et al., 2016). Both celiac and inflammatory bowel disease tend to run in families (Bonfils et al., 2025; Emilsson et al., 2015).
While the possibility of a relationship between maternal anorexia nervosa and pediatric digestive morbidity has not been considered, data suggest that other maternal mental illnesses may be linked with gastrointestinal outcomes in offspring (Davidsen et al., 2022; Heuckendorff et al., 2022). A longitudinal study of 1,477,185 children from Denmark found that maternal schizophrenia, bipolar disorder, and depression were associated with 1.6 times greater risk of digestive disorders such as esophagitis, constipation, and celiac disease in offspring (Davidsen et al., 2022). A separate Danish study found that children whose mothers had a mental illness were up to 58% more likely to develop functional gastrointestinal disorders at age 6 years (Heuckendorff et al., 2022). A cohort study from Sweden found that maternal eating disorders overall were not associated with the risk of inflammatory bowel disease in offspring (Nevriana et al., 2022), but did not examine anorexia nervosa specifically. In our analysis, children who had a mother with anorexia nervosa were 1.4 times more likely to be hospitalized for gastrointestinal morbidity before age 17 years.
Our findings suggest that some of the effects of maternal anorexia nervosa may begin in utero, as children were particularly at risk of hypertrophic pyloric stenosis. Hypertrophic pyloric stenosis is caused by narrowing of the pyloric muscle and obstruction of the gastric outlet, with symptoms generally appearing 3–6 weeks after birth (Peeters, Benninga, & Hennekam, 2012). While the etiology is not fully understood (Peeters et al., 2012), hypertrophic pyloric stenosis is thought to originate during fetal development, since the pylorus begins to form in the first trimester (Bourdelat, Barbet, & Chevrel, 1992). Some cases could relate to psychotropic medications with teratogenic properties (Kohen, 2004). Mothers may have unintentionally taken medications associated with congenital anomalies in the first trimester, as half of pregnancies in patients with anorexia nervosa are unplanned (Hoffman et al., 2011). A retrospective cohort study from Canada found that maternal mental illness, particularly depression and anxiety, was associated with an increased risk of hypertrophic pyloric stenosis in offspring (Le-Nguyen et al., 2021). Vitamin deficiency may contribute, as mothers with anorexia nervosa may lack essential nutrients required for organ development in the early stages of pregnancy. Patients with anorexia nervosa commonly have folate deficiency (Achamrah et al., 2017), a vitamin necessary to prevent neural tube defects (Williamson, 2006). Other mechanisms could be involved, as maternal anorexia nervosa remained associated with gastrointestinal morbidity after excluding children with digestive birth defects.
Some pathways may relate to maternal practices in the neonatal period, especially breastfeeding. Although guidelines recommend exclusive breastfeeding until age 6 months, mothers with anorexia nervosa are two times more likely to stop breastfeeding before 6 months than mothers without eating disorders (Torgersen et al., 2010). In our cohort, children whose mothers had anorexia nervosa were at risk of gastroenteritis and inflammatory bowel disease admission, two conditions associated with shorter breastfeeding duration (Rebhan et al., 2009; Xu et al., 2017). A meta-analysis of 14 studies found that children who were breastfed for at least 12 months were markedly less likely to develop inflammatory bowel disease than children who were breastfed for 3 or 6 months (Xu et al., 2017). Feeding practices could contribute, as mothers with anorexia nervosa may underfeed their children due to heightened concerns surrounding body size (Russell, Treasure, & Eisler, 1998).
Functional gastrointestinal disorders may also be brought on by parental anxiety. Mothers with anorexia nervosa tend to have higher levels of anxiety during pregnancy and up to 6 months postpartum than mothers with no psychiatric history (Easter et al., 2015). An analysis of longitudinal data from the United Kingdom found that children whose mothers had postpartum anxiety were 53% more likely to have recurrent abdominal pain at age 6 years (Ramchandani et al., 2006). A separate cohort study, also from the United Kingdom, found that postnatal maternal anxiety was associated with an increased risk of constipation in offspring at age 7 years (Sawyer, Heron, & Joinson, 2023). In our cohort, children whose mothers had anorexia nervosa were twice as likely to be hospitalized for constipation. Constipation and other functional disorders could be a psychosomatic manifestation of stress related to maternal anorexia nervosa. More research is needed to establish a link between anorexia nervosa and functional gastrointestinal disorders.
Genetic factors have potential to be in the pathway between maternal anorexia nervosa and pediatric digestive outcomes. Both anorexia nervosa and gastrointestinal disease have genetic components (Bonfils et al., 2025; Emilsson et al., 2015; Zipfel et al., 2015). Heritability of anorexia nervosa is estimated to be as high as 74% (Zipfel et al., 2015). Genetic transmission is thought to explain why mothers with celiac disease are 12 times more likely to have children who develop celiac disease (Emilsson et al., 2015). Having a first-degree relative with inflammatory bowel disease remains one of the most important risk factors for this condition, with affected mothers up to six times more likely to have children with inflammatory bowel disease (Bonfils et al., 2025). Data are beginning to suggest that eating disorders may share genetic risk factors with gastrointestinal disorders (Gong et al., 2023; Mostowy et al., 2016; Pascoe, Mikhail, Burt, Culbert, & Klump, 2024). A recent genome-wide association study found a strong genetic correlation between anorexia nervosa and irritable bowel syndrome, as well as overlap with inflammatory bowel disease and gastroesophageal reflux disease (Gong et al., 2023). Altered expression of AKAP6 and NTNG1 genes has been documented in children with celiac disease and individuals with anorexia nervosa (Mostowy et al., 2016). A twin study of adults from the United States found that the association between gastrointestinal disease and eating disorders was explained primarily by genetic factors (Pascoe et al., 2024).
Severity of anorexia nervosa could further play a role. Children whose mothers had multiple admissions for anorexia nervosa or hospital stays that were potentially too short were particularly at risk of gastrointestinal morbidity. Short hospital stays leading to repeated admissions for anorexia nervosa may be an indicator of a more protracted or severe maternal disease course. Maternal admissions after age 20 years were also associated with an increased risk of pediatric gastrointestinal morbidity. Anorexia nervosa beginning in adulthood may be more severe, as adults tend to have lower recovery rates than adolescents (Zipfel et al., 2015). Early identification and management of patients with severe anorexia nervosa may be a good starting point to improve the gastrointestinal outcomes of offspring. Closer efforts to optimize nutrition in pregnant patients antenatally and to promote breastfeeding postpartum may also help.
We acknowledge that this study has limitations. As we used administrative hospital data, we could not identify mothers who were treated for anorexia nervosa solely in outpatient settings or mothers who did not seek treatment. As research suggests that only around a third of individuals seek treatment (Forrest, Smith, & Swanson, 2017; Hudson, Hiripi, Pope, & Kessler, 2007), it is not clear that our findings apply to all patients with anorexia nervosa. We used the ICD-9 and 10 definition of anorexia nervosa, and did not have access to the ICD-11 in which diagnostic criteria changed. The findings may not generalize to the ICD-11 definition. We could not capture pediatric gastrointestinal disorders that were too mild to require hospital admission. Coding errors may be present, resulting in misclassification of maternal exposures or offspring outcomes. Residual confounding remains possible, as we lacked information on medication use, breastfeeding, and race and ethnicity. More research is needed to determine how socioeconomic background influences the association between maternal anorexia nervosa and pediatric gastrointestinal morbidity. Finally, the Quebec population is multicultural and has access to universal healthcare, but it is unclear whether the findings can apply to jurisdictions that do not fulfill these criteria.
In this longitudinal cohort study of nearly 1.3 million children, maternal anorexia nervosa was associated with an increased risk of hospitalization for pediatric gastrointestinal disorders, especially hypertrophic pyloric stenosis and inflammatory bowel disease. The risk of digestive morbidity was particularly elevated in children whose mothers had severe anorexia nervosa. Our findings suggest that maternal anorexia nervosa may affect offspring gastrointestinal health in the long term. Prompt identification of mothers with anorexia nervosa, including nutritional rehabilitation and psychosocial support, may help reduce the burden of pediatric digestive morbidity. Continued follow-up to encourage exclusive breastfeeding in the postpartum period may also be beneficial.
Supporting information
Auger et al. supplementary material
Acknowledgments
The authors would like to thank Nahantara Lafleur for research assistance.
Supplementary material
The supplementary material for this article can be found at http://doi.org/10.1017/S0033291725102146.
Funding statement
This work was supported by the Canadian Institutes of Health Research (grant number PJT-191702) and the Fonds de recherche du Québec – Santé (grant number 296785).
Competing interests
The authors declare none.
Ethical standard
The authors assert that all procedures contributing to this work comply with the ethical standards of the relevant national and institutional committees on human experimentation and with the Helsinki Declaration of 1975, as revised in 2008.
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