Vitamin D Supplementation In Early Pregnancy To Prevent Gestational Diabetes In Pregnant Women With Vitamin D Deficiency Or Insufficiency

Objective:Gestational diabetes mellitus（GDM）is a common complication of pregnancy that has both immediate and long-term adverse effects on the health of the mother and her child.In order to reduce the risk of developing GDM,its risk factors,especially modifiable ones,need to be fully recognised.Several risk factors associated with GDM have been identified in observational studies,including vitamin D（vitamin D,VD）deficiency,and many researchers consider vitamin D to be a potential candidate for the prevention of gestational diabetes.This article examines the effectiveness of vitamin D supplementation for the prevention of GDM in pregnant women with deficient or insufficient serum vitamin D levels in early pregnancy in a prospective study.Methods:Pregnant women with serum 25（OH）D<30 ng/m L and scheduled to have regular maternity check-ups in the hospital were recruited for delivery at the First People’s Hospital of Hefei from December 2020 to May 2022 at 12 to 13⁺⁶ weeks of gestation.The enrolled pregnant women were numbered and the corresponding serial numbers were randomly divided into the intervention and control groups using computer software to generate a random number table.Pregnant women in the intervention group were given 1200 IU/d vitamin D₃ capsules（3 capsules,400 IU/capsule）orally and continued to take them until the middle of pregnancy（24-28 weeks of gestation）,and the dose of vitamin D₃ capsules was adjusted according to the serum 25（OH）D level of women in the middle of pregnancy.In the control group,no additional vitamin D3 capsules were given and calcium tablets（1 tablet/day with 200 IU of vitamin D/capsule）were routinely recommended for pregnant women after 16 weeks’gestation according to expert consensus.The control and intervention groups were divided into three groups according to pre-pregnancy BMI:low pre-pregnancy BMI,normal pre-pregnancy BMI and overweight or obese pre-pregnancy BMI,to further explore the relationship between pre-pregnancy BMI,vitamin D supplementation during pregnancy and the risk of developing GDM.Research results:（1）There was no statistically significant difference between the age of pregnant women in the intervention group（29.79±4.29）years,pre-pregnancy BMI（21.54±2.91）kg/m² and serum vitamin D level（13.30±5.25）ng/m L and that of pregnant women in the control group（29.67±4.03）years,pre-pregnancy BMI（21.66±2.85）kg/m² and serum vitamin D level(There was no statistically significant difference between the age（29.67±4.03 years）,pre-pregnancy BMI（21.66±2.85）kg/m² and serum vitamin D level（13.44±6.31）ng/m L in the control group（P>0.05）.In the pre-pregnancy BMI groups,the differences in serum vitamin D levels between the intervention group and the control group were also not statistically significant（P>0.05）.（2）Serum vitamin D levels in the intervention group were（31.06±9.70）ng/m L in mid-pregnancy compared to（17.21±8.81）ng/m L in the control group,with a statistically significant difference between the two（P<0.001）,and the difference in serum vitamin D levels between the intervention and mid-pregnancy groups was also statistically significant（P<0.05）.In each pre-pregnancy BMI grouping,the differences in vitamin D levels between the intervention and control groups at mid-pregnancy were all statistically significant（P<0.05）.（3）As of mid-pregnancy,the differences in the five glucose metabolism indicators of fasting glucose,fasting insulin,1h postprandial glucose,2h postprandial glucose and HOMA-IR between the control and intervention groups were not statistically significant between the two values in the groups（P>0.05）.（4）The incidence rate of GDM was 19.01%in the control group and 15.56%in the intervention group,and the difference between the incidence rates of the two groups was statistically significant（P<0.05）.（5）In the control and intervention groups,which were grouped according to pre-pregnancy BMI respectively,there was no statistically significant difference in the incidence of GDM in the control group with normal pre-pregnancy BMI and the group with overweight or obesity compared with the group with low pre-pregnancy BMI（P<0.05）;The risk of developing GDM was 0.23 times（95%CI:0.05-0.89,P<0.05）and1.32 times（95%CI:0.09-1.01,P<0.05）higher in the low pre-pregnancy BMI group and the overweight or obese BMI group,respectively,than in the normal pre-pregnancy BMI group.Conclusion:In this study,we found that vitamin D supplementation in early pregnancy can increase the serum vitamin D level of pregnant women and reduce the incidence of GDM;and the intervention effect on the risk of developing GDM correlates with pre-pregnancy BMI,i.e.it decreases with higher pre-pregnancy BMI.Therefore,early vitamin D screening and early vitamin D supplementation for pregnant women with vitamin D deficiency and insufficiency are recommended;considering the potential maternal and perinatal risks of high pre-pregnancy BMI,it is recommended that pregnant women try to control their BMI to normal levels before pregnancy.