Table 2. Anthropometric and body composition measures of newborns enrolled in the Newborn Body Composition Study of the INTERGROWTH-21^st Project.

	Boys (n=501)	Girls (n=518)	Total (n=1,019)	Low-risk newbornsa (n=247)
Age at examination, h	20.8 (16.3)	19.3 (15.2)	20.0 (15.8)	17.8 (12.9)
Gestational age at delivery, weeks	39.4 (1.6)	39.4 (1.5)	39.4 (1.6)	40.0 (1.3)
Birth weight, g	3,349 (549)	3,129 (514)	3,237 (542)	3,372 (453)
Birth weight z-scoreb	0.1 (1.0)	−0.1 (1.1)	0.0 (1.1)	0.1 (0.9)
Birth length, cm	49.3 (2.3)	48.2 (2.2)	48.8 (2.3)	49.6 (2.0)
Birth length z-scoreb	−0.1 (1.1)	−0.3 (1.1)	−0.2 (1.1)	0.1 (1.0)
Head circumference, cm	34.5 (1.4)	33.6 (1.4)	34.0 (1.4)	34.3 (1.2)
Head circumference z-scoreb	0.3 (1.0)	0.1 (1.0)	0.2 (1.1)	0.3 (0.9)
Weight to length ratio, kg/m	6.7 (0.9)	6.4 (0.8)	6.5 (0.9)	6.7 (0.7)
BMI, kg/m2	13.5 (1.3)	13.2 (1.4)	13.3 (1.4)	13.4 (1.2)
Ponderal index, kg/m3	27.3 (2.3)	27.2 (2.4)	27.3 (2.4)	27.1 (2.3)
Fat mass, g	332 (172)	343 (167)	337 (170)	355 (165)
Percentage body fat, %	9.6 (4.0)	10.7 (4.0)	10.2 (4.0)	10.3 (3.9)
Fat-free mass, g	2,965 (422)	2,739 (390)	2,850 (421)	2,968 (336)

Data are mean (SD) for continuous variables or number (%) for categorical characteristics.

^aSelected according to the prescriptive criteria used to generate the INTERGROWTH-21^st Standards (3, 5).

^bCalculated for each newborn using the INTERGROWTH-21^st Newborn Size Standards (3).