Aim of work: To estimate serum 25-hydroxy vitamin D (25OH-VD) and insulin, and fasting blood glucose (FBG) early in pregnancy, determine the frequency and severity of insulin resistance (IR), gestational diabetes mellitus (GDM) and pre-eclampsia (PE) during pregnancy and the impact of VD supplemental therapy (VD-ST) on these effects.
Patients and Methods: 494 pregnant women fulfilling the inclusion criteria were randomly divided into two equal groups: Study group received VD-ST as a daily oral dose of 1000 IU soft gels with meal since 6th week till delivery, while control group did not receive VD-ST. All women gave blood samples for colorimetric estimation of FBG and ELISA estimation of serum insulin and 25-OH-VD levels. Evaluated parameters included body mass index (BMI), VD sufficiency status and homeostasis model assessment IR (HOMA-IR) score. Oral glucose tolerance test for diagnosis of GDM was performed at the 20th, 28th and 36th week GA and blood pressure was measured regularly at follow-up visits for diagnosis of PE.
Results: At time of enrolment, 405 women (81.9%) were overweight-obese, 86 women (17.4%) had IR and only 63 women (12.8%) had sufficient serum 25OH-VD level. At 3rd trimester, 68 women (13.8%) developed GDM, 71 women (14.4%) developed PE and 23 women (4.7%) developed both with significantly lower incidence in women who received VD-ST. Frequency of GDM and PE showed positive significant correlation with BMI and HOMA-IR score, while showed negative significant correlation with serum 25OH-VD. ROC curve analysis defined low 25OH-VD level and high HOMA-IR score as significant sensitive predictors for development of both GDM and PE ; while receiving VD-ST was the significant specific predictor for possibility of amelioration of such event. Kaplan-Meier regression curve defined a cumulative hazard for developing both GDM and PE of <20% with and 60% without VD-ST.
Conclusion: VD deficiency-insufficiency is a problem that requires national evaluation for predisposition and progress. The triad of maternal hypovitaminosis D, obesity and IR is associated with development of GDM and/or PE. The proposed VD supplementation regimen effectively reduced the frequencies of pregnancy-associated or induced complications; so it is effective to break that triad.