Figure 2.

Term placental tissue was probed for 1α-hydroxylase mRNA expression and ΔΔCt values were plotted against maternal concentrations of calcitriol at midgestation (A). Placental CYP27B1 expression was found to be significantly, positively correlated with maternal serum calcitriol at midgestation (P = .002, n = 49, R² = 0.19). Placental protein expression of CYP27B1 was found to be significantly positively associated with maternal 25(OH)D concentrations at both midgestation (P = .009, n = 68, R² = 0.10; B) and delivery (P = .006, n = 67, R² = 0.11, data not shown).