RESUMO
Objective To analyze the serum level of 25-hydroxy vitamin D [25-(OH) D] in pregnant women in Nanjing and its relationship with age,gestational week,pre-pregnancy body mass index (BMI) and season,so as to provide some guidance on clinical application of vitamin D measurement and supplementation.Methods 880 pregnant women (in 21-36 gestational weeks) regularly visiting antenatal clinic in Obstetrics and Gynecology Hospital Affiliated to Nanjing Medical University were selected from January to December 2015.Their serum 25-(OH)D concentrations were measured by enzyme-linked immunosorbent assay (ELISA).Results The mean serum 25-(OH) D concentration in these pregnant women was (42.03 ± 19.22) nmol/L and sufficient in only 42 (4.77％).Vitamin D levels showed seasonal variation (P =0.0164),with the levels in summer [(44.61 ±23.57) nmol/L] and autumn [(43.43 ± 19.31) nmol/L] being higher than spring [(39.68 ± 16.91) nmol/L] and winter [(39.65 ± 13.36) nmol/L].There was no statistically significant difference in serum vitamin D level among different gestational weeks (P =0.929 4).There was statistically significant difference in serum vitamin D level among different age groups (P =0.038 3).Vitamin D level was not associated with pre-pregnancy BMI.Conclusions Vitamin D deficiency is highly prevalent among pregnant women in Nanjing.We suggest vitamin D testing be carried out more actively.