Table 1.

Definition criteria of functional constipation (FC) used by studies and the new Rome IV criteria

Evolution of the definition for functional constipation: from Rome II to IV
FC criteria	Rome II (1999)		PACCT (2005)	Rome III (2006)		Rome IV (2016)
Age (years)	0–4	0–16	Children with chronic constipation with or without treatment who still fulfill criteria	0–4	4- to adolescent	0–4	4- to adolescent
Type of constipation	FC	FFR	FC	FC	FC	FC	FC
Duration of symptoms	At least 2 weeks	At least 12 weeks	8 weeks or more	Must include at least 1 month	Once a week for at least 2 months or more	Must include at least 1 month	Once a week for at least 1 month
Number of criteria needed	At least 1	2 needed/all needed	At least 2 or more	At least 2 or more	At least 2 or more	At least 2 or more	At least 2 or more
Diagnostic criteria	Majority of stools scybalous, pebble-like, hard or	Passage or large diameter <2 times/week and	<3 defecations/week	2 or fewer defecations/week	2 or fewer defecations in the toilet/week	2 or less defecations/week	2 or less defecations in the toilet/week
	Firm stools 2×/week or less	Retentive posturing, avoiding defecation by purposefully contracting the pelvic floor. Child uses gluteal muscles, squeezing the buttocks together	>1 episode of fecal incontinence/week	At least 1 episode of fecal incontinence/week after acquisition of toilet skills	At least 1 episode of fecal incontinence/week	Excessive stool retention	At least 1 episode of fecal incontinence/week
			Stool-retentive posturing	Excessive stool retentive	Stool-retentive posturing or excessive volitional stool retention	Stool-retentive posturing	Stool-retentive posturing or excessive volitional stool retention
			Hard or painful bowel movements	Hard or painful bowel movements	History of painful or hard bowel movement	History of painful or hard bowel movement	History of painful or hard bowel movement
						Large fecal mass in rectum
						Toilet trained children additional criteria	–
			Large-diameter stools that could obstruct the toilet	Large-diameter stools that could obstruct the toilet	Large-diameter stools that could obstruct the toilet	At least 1 episode of fecal incontinence/week	Large-diameter stools that could obstruct the toilet
			Large fecal mass in rectum or palpable in abdomen	Large fecal mass in rectum	Large fecal mass in rectum	Large-diameter stools that could obstruct the toilet	Large fecal mass in rectum/the toilet
Exclusion criteria	No metabolic endocrine, structural disease	No metabolic endocrine, structural disease	–	• Must have insufficient criteria for diagnose of irritable bowel syndrome. • Symptoms cannot be fully explained by another medical condition.		• Must have insufficient criteria for diagnose of irritable bowel syndrome. • Symptoms cannot be fully explained by another medical condition.

Note: “–”= Not available.

Abbreviations: FC, functional constipation; FFR, functional fecal retention; PACCT, Paris Consensus on Childhood Constipation Terminology.