TABLE 1.

Summary of the effects of intrauterine growth restriction on the small intestine from selected studies¹

Reference	Species	Age measured2	Small-intestinal mass or length response	Additional small-intestinal responses
28	Sheep	Day 140 gestation	↓Mass; ↓length	↓Villus and crypt density; ↓villus height and crypt depth; ↓mucosal thickness
29	Sheep	Day 90 gestation	↓Mass; ↓relative mass	↓Mucosal circumference and area; ↓crypt depth; abnormal enterocyte differentiation
30	Rabbits	Day 31 gestation	Not determined	↓Villus height; ↓ proliferation; ↑ epidermal growth factor mRNA
31	Rats	Birth–12 wk	↓Mass (to 4 wk); ↓length (to 12 wk)	↑Maltase (at birth); ↑lactase (at birth)
32	Pigs	Birth	↓Mass; ↓length	↓Mucosal weight; ↓IGF-1 mRNA expression
33	Pigs	Birth	↓Mass; ↓relative mass	Altered proteome
34	Pigs	Birth–5 d	↓Mass (to 2 d); ↓length (to 5 d)	↓Villus height (to 2 d); ↓villus width (at 2 d); ↑adherent bacterial number; altered transcriptome

¹IGF-1, insulin-like growth factor 1; ↓, decreased; ↑, increased.

²Approximate gestation lengths: sheep = 150 d, rabbits = 31 d.