Vitamin D and Health

vitamin D deficient rats and VDR-null mice indicate that vitamin D is not required for this. Pregnancy
induced adaptations to maternal calcium homeostasis seem to meet fetal requirements for calcium.
Although skeletal resorption can also release calcium into the circulation, the evidence is mixed on
whether the maternal skeleton contributes substantial amounts of calcium to the fetus (Kovacs,
2008).
6.50 The relationship between bone health indices and maternal serum 25(OH)D concentration during
pregnancy is unclear which complicates associations between serum 25(OH)D concentration and bone
health indices during this time (Brannon & Picciano, 2011).
6.51 Physiological changes that occur during pregnancy increase serum concentrations of 1,25(OH) 2 D and
DBP; serum 25(OH)D concentration, however, remains unaffected. The underlying mechanisms for
these changes are not clearly understood (Brannon & Picciano, 2011).
6.52 IOM report: The IOM identified only 1 cohort study which included maternal BMD as an outcome and
reported no relationship between serum 25(OH)D concentration and postpartum changes in BMD. It
concluded that there was insufficient evidence for an association between a specific serum 25(OH)D
concentration and BMC or BMD.
Evidence considered since IOM report
Maternal outcomes
Intervention studies
6.53 No RCTs investigating effects of vitamin D supplementation during pregnancy/lactation on markers of
maternal bone health have been published since the IOM report.
Cohort studies
6.54 A study in Turkey (Haliloglu et al., 2011) investigated the relationship between serum 25(OH)D
concentration and CTX in women (n=30; mean age, 28y) receiving supplemental vitamin D 3
(10 µg/400 IU per day) during pregnancy and lactation. Mean serum 25(OH)D concentration was 19.1,
15.7, 11.1 and 7.0 nmol/L during the 1 st , 2 nd and 3 rd trimester and postpartum period respectively. No
correlation was found between serum 25(OH)D and CTX concentration in the 1st trimester but there
was a negative correlation in the 2nd and 3rd trimesters and the postpartum period (r = -0.47,
p=0.048; r= -0.89, p