Vitamin D deficiency and placental calcification in low-risk obstetric population: are they related?

Objective: We aimed to evaluate the relationship between placental calcification and maternal and cord blood 25-hydroxyvitamin-D3 [25(OH)D] and calcium concentrations in low-risk obstetric population at term and their consequences.

Methods: Sixty non-complicated pregnant women at term admitted to maternity clinic were included in this prospective case-control study and classified into one of two groups according to grade of placental calcification by defined the Grannum classification: Group 1 (n=30), with Grade 3 placenta and Group 2 (n=30), the control group, no placental calcification noted. Baseline characteristics, maternal serum and umbilical cord 25(OH)D and calcium levels were compared between groups.

Results: The mean age of subjects was 26.4 ± 5.7 years. The mean serum 25(OH)D concentration of women (n=60) was 9.3 ± 3.4 (range 5.59-15.48) ng/mL. The prevalence of vitamin D deficiency [25(OH)D <20 ng/mL] was 100%. Maternal serum and cord blood calcium levels were significantly higher in Group 1 (p=0.036; p=0.037, respectively). In Group 2, maternal serum and cord blood 25(OH)D levels were higher than Group 1 (11.35 ± 6.54 and 10.22 ± 3.59 versus 9.6 ± 4.2 and 9.07 ± 2.43 ng/mL); but the difference is not statistically significant.

Conclusions: Higher maternal calcium and lower 25(OH)D levels detected in patients with Grade 3 placental calcification indicated the importance of placenta on vitamin D regulation.