Vitamin D deficiency is a common finding in overweight/obese pregnant women and is associated with increased risk for adverse pregnancy outcome. Both maternal vitamin D deficiency and maternal obesity contribute to metabolic derangements in pregnancy. We aimed to assess the effects of vitamin D3 supplementation in pregnancy versus placebo on maternal and fetal lipids. Main inclusion criteria were: women <20 weeks’ gestation, BMI ≥ 29 kg/m². Eligible women (n = 154) were randomized to receive vitamin D3 (1600 IU/day) or placebo. Assessments were performed <20, 24–28 and 35–37 weeks and at birth. Linear regression models were used to assess effects of vitamin D on maternal and cord blood lipids. In the vitamin D group significantly higher total 25-OHD and 25-OHD3 levels were found in maternal and cord blood compared with placebo. Adjusted regression models did not reveal any differences in triglycerides, LDL-C, HDL-C, free fatty acids, ketone bodies or leptin between groups. Neonatal sum of skinfolds was comparable between the two groups, but correlated positively with cord blood 25-OH-D3 (r = 0.34, p = 0.012). Vitamin D supplementation in pregnancy increases maternal and cord blood vitamin D significantly resulting in high rates of vitamin D sufficiency. Maternal and cord blood lipid parameters were unaffected by Vitamin D3 supplementation.

Aims: To compare glycemic control and maternal–fetal outcomes of women with type 1 diabetes (T1D) using hybrid closed loop (HCL) vs. multiple daily insulin injections (MDI) plus continuous glucose monitoring (CGM). Methods: Multicenter prospective cohort study of pregnant women with T1D in Spain. We evaluated HbA1c and time spent within (TIR), below (TBR) and above (TAR) the pregnancy-specific glucose range 3.5–7.8 mmol/L. Adjusted models were performed for adverse pregnancy outcomes including baseline maternal characteristics and center. Results: 112 women were included (HCL n=59). Women in the HCL group had a longer duration of diabetes and higher rates of prepregnancy care. There were no between-group differences in HbA1c in any trimester. However, in the second trimester, MDI users had a greater decrease in HbA1c (-6.12±9.06 vs. -2.16 ±7.42 mmol/mol, p=0.031). No differences in TIR (3.5-7.8 mmol/L) and TAR were observed between HCL and MDI users, but with a higher total insulin dose in the second trimester (+0.13 IU/Kg/d). HCL therapy was associated with increased maternal weight gain during pregnancy (βadjusted 3.20 kg, 95%CI 0.90-5.50). Regarding neonatal outcomes, newborns of HCL users were more likely to have higher birthweight (βadjusted 279.0 g, 95% CI 39.5-518.5) and macrosomia (ORadjusted 3.18, 95% CI 1.05-9.67) compared to MDI users. These associations disappeared when maternal weight gain or third trimester HbA1c were included in the models. Conclusions: In a real-world setting, HCL users gained more weight during pregnancy and had larger newborns than MDI users, while achieving similar glycemic control in terms of HbA1c and TIR.

Studies on the relationship between vitamin D (VitD) and glucose homeostasis usually consider either total VitD or 25OHD3 but not 25OHD2 and epimers. We aimed to evaluate the cross-sectional association of VitD compounds with glucose homeostasis measurements in pregnant women with overweight/obesity participating in the Vitamin D And Lifestyle Intervention for Gestational Diabetes Mellitus Prevention study. Methods: The analysis included 912 women. Inclusion criteria: <20 weeks gestation, body mass index ≥29 kg/m² and information on exposure and outcome variables at baseline. Measurements: A 75 g OGTT at <20, 24–28 and 35–37 weeks gestation (except if previous diabetes diagnosis). Exposure variables: 25OHD2, 25OHD3 and C3-epimer. Outcome variables: fasting and post-challenge insulin sensitivity and secretion indices, corresponding disposition indices (DI), plasma glucose at fasting and 1 and 2 h, hyperglycemia in pregnancy (HiP). Statistics: Multivariate regression analyses with adjustment. Results: Baseline VitD sufficiency was 66.3%. Overall, VitD compounds did not show strong associations with any glucose homeostasis measures. 25OHD3 showed direct significant associations with: FPG at <20 and 24–28 weeks (standardized β coefficient (β) 0.124, p = 0.030 and 0.111, p = 0.026 respectively), 2 h plasma glucose at 24–28 weeks (β 0.120, p = 0.018), and insulin sensitivity (1/HOMA-IR, β 0.127, p = 0.027) at 35–37 weeks; it showed an inverse association with fasting DI (QUCKI*HOMA-β) at <20 and 24–28 weeks (β −0.124, p = 0.045 and β −0.148, p = 0.004 respectively). 25OHD2 showed direct associations with post-challenge insulin sensitivity (Matsuda, β 0.149, p = 0.048) at 24–28 weeks) and post-challenge DI (Matsuda*Stumvoll phase 1) at 24–28 and 35–37 weeks (β 0.168, p = 0.030, β 0.239, p = 0.006). No significant association with C3-epimer was observed at any time period. Conclusions: In these women with average baseline VitD in sufficiency range, VitD compounds did not show clear beneficial associations with glucose homeostasis measures.