Gastrointestinal pH, emptying, transit time, and length in human term and preterm neonates compared with adults

Data are representative of original study reports. Because of variability in study populations, measurement techniques, and reporting, ranges of observed values or ranges of means are provided.

Human Term Neonate (GWs 37+)Human Preterm Neonate (GWs < 37)Adult Human
 Fasted2.0–6.1 (Mason, 1962; Fredrikzon and Hernell, 1977)1.8–4.9 (Sondheimer et al., 1985; Kelly et al., 1993; Armand et al., 1996; Omari and Davidson, 2003)a1.4–2.1 (Dressman et al., 1990)b
 Fed (enterally)5.2–7.5 (Mason, 1962; Fredrikzon and Hernell, 1977)4.5–7.2 (Smith et al., 1986; Armand et al., 1996; Omari and Davidson, 2003)a4.3–5.4 (Dressman et al., 1990)b
 Small intestine5.8–7.0 (duodenum, fed) (Barbero et al., 1952)∼7 (duodenum, fed) (Fredrikzon and Olivecrona, 1978)a5.8–6.5 (duodenum, fasted) (Dressman et al., 1990)b
 Large intestine7–8.2 (cecum, fed) (Barbero et al., 1952)ND7.4–8.0 (ascending colon, fasted) (Diakidou et al., 2009)c
Gastric emptying (t1/2)
 Water or aqueous4.5–8.0 min (Lange et al., 1997)4.0–8.5 min (Lange et al., 1997)11–17 min (Steingoetter et al., 2006; Mudie et al., 2014)d
 Human milk48 ± 15 min (Cavell, 1981)e12–180 min (Cavell, 1979; Bode et al., 2004)NA
 Infant formula78 ± 14 min (Cavell, 1981)f32–64 min (Cavell, 1979)(liquid test meal) 10–110 min (Maes et al., 1995)
Intestinal transit time
 SITT4 hfND0.53–4.1 h (liquid transit) (Graff et al., 2001; Bouras et al., 2004)
 OCT1.2–2.0 h (Vreugdenhil et al., 1986)1.3–6.1 h (Cavell, 1979; Bode et al., 2004)0.5–2.3 h (Vreugdenhil et al., 1986)
  • ND, no data.

  • a Estimated from graphical representation of means; range not reported.

  • b Interquartile range of 34 healthy volunteers (12–35 years; 18 female, 16 male).

  • c Interquartile range of 12 healthy volunteers (19–28 years; 6 female, 6 male).

  • d Fasted conditions.

  • e Reported mean and error (Cavell, 1981).

  • f Reference value reported in ICRP (2002).