Abstract: Objective To investigate the relationship between serum uric acid level and 25 hydroxyvitamin D₃[25(OH)VD₃] in women in the second trimester of pregnancy.Method A total of 221 women in second trimester of pregnancy were selected and their age,gestational weeks and other general data were collected.The liver and renal function,fasting plasma glucose(FPG),thyroid function and 25(OH)VD₃ levels were measured.According to the 25(OH)VD₃ levels,they were divided into vitamin D deficiency group[25(OH)VD₃<50 nmol/L] and vitamin D appropriate group[25(OH)VD₃≥50nmol/L].The clinical data of the two groups were compared and the factors influencing the level of 25(OH)VD₃ were analyzed.Results In 221 women of second trimester,vitamin D deficiency was present in 147 cases(67%) and Vitamin D was appropriate in 74 cases(33%).Levels of serum uric acid,thyrotrophin (TSH),gestational week in the vitamin D deficiency group were all lower than those in the vitamin D appropriate group,while levels of free thyroxine (FT₄),FPG and total bilirubin (TBIL) were higher than those in the vitamin D appropriate group,with statistically significant differences(P<0.05).Correlation analysis showed that 25(OH)VD₃ level in the second trimester of pregnancy was positively correlated with serum uric acid，TSH and gestational age，while was negatively correlated with FT₄ and TBIL (P<0.05).Logistic regression analysis showed that serum uric acid reduction was a risk factor for the deficiency of 25(OH)VD₃ (OR=1.008,P=0.024).Conclusion Vitamin D deficiency is common in women in the second trimester of pregnancy.The gestational age，serum uric acid,FT₄,TSH and TBIL are associated with the reduction of 25(OH)VD₃.Serum uric acid reduction is the main risk factor for 25(OH)VD₃ deficiency.

Key words: 25 hydroxyvitamin D₃, Serum uric acid, Second trimester of pregnancy