Maternal plasma vitamin D levels across pregnancy are not associated with neonatal birthweight: findings from an Australian cohort study of low-risk pregnant women

Table 4 Associations of maternal vitamin D across pregnancy with maternal gestational weight gain and BMI

Vitamin D measureª	Weight outcome	β (95% CI)	P-value
Early pregnancy
Crude	GWG (kg)	-0.01 (-0.04, 0.02)	0.497
Crude	late BMI (kg/m²)	-0.02 (-0.05, 0.01)	0.201
Adjusted^c	GWG (kg)	-0.02 (-0.05, 0.02)	0.333
Adjusted^c	late BMI (kg/m²)	-0.01 (-0.03, 0.00)	0.058
Mid pregnancy
Crude	GWG (kg)	0.01 (-0.01, 0.03)	0.415
Crude	late BMI (kg/m²)	-0.03 (-0.06, -0.01)	0.003
Adjusted^c	GWG (kg)	0.00 (-0.02, 0.02)	0.791
Adjusted^c	late BMI (kg/m²)	-0.01 (-0.01, 0.00)	0.271
Late pregnancy
Crude	GWG (kg)	0.00 (-0.02, 0.03)	0.676
Crude	late BMI (kg/m²)	-0.04 (-0.06, -0.01)	0.002
Adjusted^c	GWG (kg)	0.00 (-0.02, 0.02)	0.827
Adjusted^c	late BMI (kg/m²)	0.00 (-0.02, 0.01)	0.504
Vitamin D deficiency^b	Weight outcome	β (95% CI)	P-value
Early pregnancy
Crude	GWG (kg)	-1.64 (-4.54, 1.25)	0.263
Crude	late BMI (kg/m²)	0.11 (-2.79, 3.02)	0.938
Adjusted^c	GWG (kg)	-1.32 (-4.22, 1.59)	0.371
Adjusted^c	late BMI (kg/m²)	-0.48 (-1.72, 0.75)	0.441
Mid pregnancy
Crude	GWG (kg)	-3.13 (-5.62, -0.65)	0.014
Crude	late BMI (kg/m²)	1.39 (-1.28, 4.06)	0.307
Adjusted^c	GWG (kg)	-2.70 (-5.23, -0.17)	0.037
Adjusted^c	late BMI (kg/m²)	-0.89 (-2.01, 0.23)	0.117
Late pregnancy
Crude	GWG (kg)	-1.34 (-3.98, 1.31)	0.320
Crude	late BMI (kg/m²)	2.45 (-0.39, 5.29)	0.090
Adjusted^c	GWG (kg)	-0.86 (-3.54, 1.81)	0.525
Adjusted^c	late BMI (kg/m²)	-0.26 (-1.45, 0.94)	0.671

ªSerum 25(OD)D
^bvitamin D deficiency defined as defined as serum 25(OH)D < 50 nmol/L; GWG and BMI (continuous outcomes); GWG (gestational weight gain); BMI (body mass index)
^cModels adjusted for maternal age, region of birth, early pregnancy BMI and education

ISSN: 1471-2393