Gastrointestinal consequences of cesarean section birth: A systematic review of short- and long-term effects in infancy and beyond

Table 13 Summary of key studies on cesarean section and food allergy risk

Ref.	Country	Sample size	Follow-up	Association with food allergy	Modifiable factors	Risk of bias
Papathoma et al[71], 2016	Greece	459	3 years	↑ C-section risk (OR: 3.15); higher with parental atopy	Atopic dermatitis, gestational age	Moderate (small sample, good confounder adjustment)
Eggesbø et al[72], 2003	Norway	2803	2.5 years	↑ Risk in allergic mothers (OR: 7.0)	Antibiotics not significant	Low (strong prospective design, adjusted)
Mitselou et al[73], 2018	Sweden	1086378	13 years	HR: 1.21 for C-section	LGA, low Apgar score	Low (large population-based cohort)
Pyrhönen et al[74], 2022	Finland	5564	12 years	RR: 2.41 for elective C-section in non-atopic mothers	Sibling atopy modifies risk	Moderate (targeted subgroup, adjusted analysis)
Polos and Fletcher[75], 2019	United States	150000+	Cross-sectional	↑ Food allergy across racial groups	Race, C-section rate, birth cohort effects	Moderate (large dataset, cross-sectional limitations)
Currell et al[76], 2022	Australia	5276	12 months	No association with C-section (aOR: Approximately 1.0)	Labor, feeding, siblings not modifying	Low (clear methodology and control)
Chua et al[77], 2025	Taiwan	> 1 million	Approximately 14 years	No significant food allergy risk (aHR: 1.13)	↑ Asthma, eczema, obesity	Low (nationwide cohort, adjusted)
Tamai et al[78], 2025	Japan	2114	9 years	No significant association (aRR: 1.1; CI: 0.7-1.7)	Adjusted for child & parental variables	Low (population-based, adjusted with GEE)
Adeyeye et al[79], 2019	United States	Approximately 2900	3 years	↑ Risk with emergency C-section (RR: 3.02)	Breastfeeding (partial mediation)	Moderate (good adjustment, moderate size)
Yang M et al[80], 2019	China	6768	12 months	↑ C-section and formula feeding in CMPA group	High tolerance after 1 year (77%)	Moderate (well-documented, short-term)
Gil et al[81], 2017	Spain	211 cases + controls	Retrospective	C-section + formula (FFH) ↑ risk (OR: 11.82)	FFH and breastfeeding key risk factors	Moderate (case-control, smaller scale)
Metsälä et al[82], 2010	Finland	16237 CMPA cases	2 years	C-section (OR: 1.18); high maternal age ↑ risk	Smoking & low SES ↓ risk	Low (large birth cohort, adjusted)
Toro Monjaraz et al[83], 2015	Mexico	101 CMPA, 90 controls	Retrospective	No C-section effect; antibiotics ↑ risk	Breastfeeding duration ↓ risk	High (small sample, retrospective)
Kuitunen et al[84], 2009	Finland	1018	5 years	Probiotics ↓ allergy in C-section-born infants	Perinatal probiotic supplementation	Moderate (well-executed trial, modest size)

Clinical Pearls 7: Cesarean section, primarily when elective and without labor, is associated with a modestly increased risk of food allergies, including cow’s milk protein allergy. This risk is amplified by factors such as formula feeding, the absence of breastfeeding, and early exposure to antibiotics. Promoting exclusive breastfeeding and early microbial support (e.g., probiotics or synbiotics) may help reduce the development of allergies in cesarean section-born infants. aRR: Adjusted risk ratio; CMPA: Cow’s milk protein allergy; C-section: Cesarean section; FFH: Formula feeding in hospital; GEE: Generalized estimating equations; HR: Hazard ratio; LGA: Large for gestational age; OR: Odds ratio; SES: Socioeconomic status.