Lumbar spine bone mass in the neonatal period according to gestational weight gain categories and maternal 25(OH)D status. Data are reported as mean ± SD and were analyzed using mixed linear model accounting for the fixed effects of the infant’s sex, age, and LAZ score and the mother’s 25(OH)D categories, pre-pregnancy BMI categories, gestational weight gain categories, education, self-reported population group, as well as family income (p < 0.05, post hoc adjustment). Abbreviations: 25(OH)D: 25-hydroxyvitamin D, LS BMC: lumbar spine bone mineral content, and LS BMD: lumbar spine bone mineral density.