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

Table 1 Population, intervention, comparison, outcome, inclusion, and exclusion criteria

PICO element	Description
Research question	What are the short- and long-term gastrointestinal effects in infants born via C-section compared to those born via vaginal delivery?
Population (P)	Infants born via C-section (elective or emergency), from term or preterm gestations, across various geographic and ethnic backgrounds
Intervention (I)	Birth by C-section (elective or emergency)
Comparison (C)	Infants born via vaginal delivery (with or without labor)
Outcome (O)	Short- and long-term gastrointestinal outcomes, including gut dysbiosis, functional gastrointestinal disorders, infantile colic, constipation, gastroesophageal reflux, inflammatory bowel disease, food allergies (including cow’s milk protein allergy), and coeliac disease
Study design	Systematic review of observational studies (cohort, case-control, cross-sectional), randomized controlled trials, and relevant systematic reviews/meta-analyses
Other	Inclusion: Human studies, studies reporting delivery mode and gastrointestinal outcomes, studies with clearly defined outcome measures, and English language. Exclusion: Case reports, animal studies, conference abstracts without full data, studies not distinguishing C-section from vaginal delivery or lacking gastrointestinal outcomes

PICO: Population, intervention, comparison, outcome; C-section: Cesarean section.