Table 1.
Associations of maternal iron parameters with birthweight by hierarchical regression

Variables	Model 1		Model 2
	β	P-value	β	P-value
Age	0.114	0.029	0.115	0.027*
Parity	0.110	0.037	0.088	0.096
Height	0.094	0.059	0.108	0.030*
BMIa	0.201	0.000	0.210	0.000*
Gestational age	0.312	0.000	0.298	0.000*
Hemoglobin			–0.081	0.140
Iron			–0.049	0.377
TIBCb			0.088	0.102
Ferritin			0.017	0.754
R2 (adjusted R2)	0.161 (0.149)		0.185 (0.163)
F (P)	13.331 (0.000*)		8.632 (0.000*)

Statistically significant.
β: standardized coefficient.
BMI: body mass index.
TIBC: total iron-binding capacity.