Bone calcium turnover is aggravated in pregnant women recommended to bed rest. In the present cross-sectional study, we aimed to clarify whether preterm neonates would benefit from calcium supplementation during pregnancy. Forty-two mothers (37.5 ± 6.7 years), recommended bed rest at home, and 42 preterm neonates (24-37 weeks gestational age) were enrolled. Neonates' serum calcium was quantified at birth. Mothers' calcium intake from foods and supplements during pregnancy was assessed. Serum 25-OH-D was measured in both mothers and neonates at birth. Results showed that mothers' calcium intake from foods was significantly lower than the recommended daily reference value (p < 0.001), while total calcium intake including supplements was close to the calcium reference value of 1000 mg/day (p = 0.648). Neonates' serum calcium concentration was significantly higher in mothers receiving calcium supplementation during pregnancy compared to mothers who did not (p < 0.001). A significant association between neonates' serum calcium levels and mothers' calcium supplementation was evident, even when adjusted to mothers' age, pre-pregnancy BMI, gestational age, and neonates' birth weight (beta = +0.460, p = 0.025). A statistically significant correlation between neonates' and mothers' serum 25-OH-D levels was found (r = 0.891, p < 0.001). In conclusion, calcium status in preterm neonates, born by bedridden women, could be enhanced after calcium supplementation during gestation.
Keywords: bed rest; calcium supplement; dietary calcium; pregnancy; preterm neonates; vitamin D.