Vitamin D insufficiency, preterm delivery and preeclampsia in women with type 1 diabetes – an observational study

Abstract

Introduction. The aim of this study was to evaluate whether vitamin D insufficiency is associated with preterm delivery and preeclampsia in women with type 1 diabetes. Material and methods. An observational study of 198 pregnant women with type 1 diabetes. 25-Hydroxy-Vitamin D and HbA1c were measured in blood samples in early (median 8 weeks, range 5-14) and late (34 weeks, range 32-36) pregnancy. Kidney involvement (microalbuminuria or nephropathy) at inclusion, smoking status at inclusion, preterm delivery (<37 weeks) and preeclampsia (blood pressure ≥140/ 90 mmHg and proteinuria) were registered. Vitamin D supplementation of 10 lg daily was routinely recommended. Results. Thirty-nine (20%) of the 198 women delivered preterm and 16 (8%) developed preeclampsia. Vitamin D insufficiency (<50 nmol/L) was present in 68 women (34%) in early pregnancy and in 73 women (37%) in late pregnancy. Preterm delivery occurred more frequently in women with vitamin D insufficiency in late pregnancy (27% vs. 15%, crude odds ratio 2.1; 95% confidence interval 1.0-4.3, p = 0.04). After adjustment for preexisting kidney involvement, HbA1c in late pregnancy and smoking the association became nonsignificant (adjusted odds ratio 1.8; 95% confidence interval 0.8-3.7). Preeclampsia developed in 11% of women with vitamin D insufficiency vs. 6% of the remaining women (crude odds ratio 1.8; 95% confidence interval 0.9-4.1, p = 0.25). Conclusion. In women with type 1 diabetes, preterm delivery was twice as frequent in women with vitamin D insufficiency in late pregnancy in crude analysis, but in this small study, low vitamin D was not independently associated with preterm birth or preeclampsia.

Vitamin D Metabolites and Binding Protein Predict Preeclampsia in Women with Type 1 Diabetes

“…Some studies in non-diabetic pregnant women have suggested that low total 25(OH)D is associated with contemporaneous [10] or subsequent PE [9,12], perhaps limited to early-onset disease [13]. Our present finding of no significant association is consistent with our previous study (that used different methodology to measure 25(OH)D) [30] and with a study by Vestgaard et al [17]. The present work extends those findings, showing that neither bioavailable nor free forms of 25(OH)D predicted PE, with the caveat that our cohort did not contain vitamin D-sufficient women.…”

“…By contrast, 25(OH)D, the standard metric for vitamin D, did not predict PE; of note, however, insufficient or deficient levels were almost universal in our diabetic cohort. Reported associations of vitamin D deficiency in diabetic pregnancy include preterm birth, increased T1DM rates in offspring of women with T1DM, and poor glycemic control [12,17,20,21,29]. Some studies in non-diabetic pregnant women have suggested that low total 25(OH)D is associated with contemporaneous [10] or subsequent PE [9,12], perhaps limited to early-onset disease [13].…”

“…In the general population, the plasma concentration of 25-hydroxyvitamin D (25(OH)D), the prohormone and precursor of 1,25(OH) 2 D, is considered the principal metric for assessing vitamin D status: deficiency and insufficiency are defined as <20 and <32 ng/mL (<50 and <80 nmol/L), respectively [7]. Vitamin D deficiency is associated with poor pregnancy outcomes for both mother and child [2,[8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Both 25(OH)D and 1,25(OH) 2 D can be measured in plasma as total, bioavailable, and free forms; both metabolites are highly lipophilic and, in plasma, are almost entirely protein-bound.…”

“…Women with type 1 diabetes (T1DM) have a markedly increased risk for PE (~20% vs.~5% in the general population) [28]. Vitamin D deficiency is associated with abnormal placentation, altered angiogenesis, immune dysfunction, abnormal insulin secretion and action, adverse lipid profiles, and inflammation: problems that are also associated with diabetes [2,4,11,[13][14][15][16][17]19,29]. Vitamin D deficiency may also be implicated in PE [9,13].…”

Maternal Diabetes Mellitus – Risk Factor for Fetus and Infant

“…Recently, Danish authors have reported a study of 198 pregnant women with type 1 diabetes; in the research group, insufficient vitamin D intake (<50 nmol/l) was observed in as many as 68 women (34%). [12] Vitamin D supplementation of 1500-2000 IU/d is recommended. [13]…”