Vitamin D Supplementation and the Effects on Glucose Metabolism During Pregnancy: A Randomized Controlled Trial
Diabetes Care April 23, 2014
Constance Yap1,2⇑, Ngai W. Cheung1,2, Jenny E. Gunton1,2,3, Neil Athayde4, Craig F. Munns5, Anna Duke1 and Mark McLean1,6
1Diabetes and Endocrinology, Westmead Hospital, Sydney, New South Wales, Australia
2Faculty of Medicine, Western Clinical School, University of Sydney
3Diabetes and Transcription Factors Group, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
4Obstetrics and Gynaecology, Westmead Hospital, Sydney, New South Wales, Australia
5Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
6School of Medicine, University of Western Sydney, Sydney, New South Wales, Australia
Corresponding author: Constance Yap, constanceyap at yahoo.com.
OBJECTIVE Vitamin D deficiency in pregnancy is associated with an increased risk of gestational diabetes mellitus (GDM) and neonatal vitamin D deficiency. We conducted a double-blind, randomized controlled trial of low-dose (LD) versus high-dose (HD) vitamin D supplementation to investigate the effects of vitamin D supplementation on glucose metabolism during pregnancy.
RESEARCH DESIGN AND METHODS Women with plasma 25-hydroxyvitamin D (25OHD) levels <32 ng/mL before 20 weeks’ gestation were randomized to oral vitamin D3 at 5,000 IU daily (HD) (n = 89) or the recommended pregnancy dose of 400 IU daily (LD) (n = 90) until delivery. The primary end point was maternal glucose levels on oral glucose tolerance test (OGTT) at 26–28 weeks’ gestation. Secondary end points included neonatal 25OHD, obstetric and other neonatal outcomes, and maternal homeostasis model assessment of insulin resistance. Analysis was by intention to treat.
RESULTS There was no difference in maternal glucose levels on OGTT. Twelve LD women (13%) developed GDM versus seven (8%) HD women (P = 0·25). Neonatal cord 25OHD was higher in HD offspring (46 ± 11 vs. 29 ± 12 ng/mL, P < 0.001), and deficiency was more common in LD offspring (24 vs. 10%, P = 0.06). Post hoc analysis in LD women showed an inverse relationship between pretreatment 25OHD and both fasting and 2-h blood glucose level on OGTT (both P < 0·001). Baseline 25OHD remained an independent predictor after multiple regression analysis.
CONCLUSIONS HD vitamin D supplementation commencing at a mean of 14 weeks’ gestation does not improve glucose levels in pregnancy. However, in women with baseline levels <32 ng/mL, 5,000 IU per day was well tolerated and highly effective at preventing neonatal vitamin D deficiency.
See also Vitamin D Life
- Preeclampsia reduced by Vitamin D (50,000 IU bi-weekly) and Calcium – Oct 2015
- Gestational Diabetes mostly treated with just 2 doses of 50,000 IU of vitamin D – RCT Dec 2013
- Search Vitamin D Life for Preeclampsia 408 items as of Oct 2015
- Why preeclampsia is 5X more likely if vitamin D insufficient – Jan 2015
- Preeclampsia rate cut in half by high level of vitamin D – meta-analysis March 2014
- Overview Pregnancy and vitamin D has the following summary
IU | Cumulative Benefit | Blood level | Cofactors | Calcium | $*/month |
200 | Better bones for mom with 600 mg of Calcium | 6 ng/ml increase | Not needed | No effect | $0.10 |
400 | Less Rickets (but not zero with 400 IU) 3X less adolescent Schizophrenia Fewer child seizures | 20-30 ng/ml | Not needed | No effect | $0.20 |
2000 | 2X More likely to get pregnant naturally/IVF 2X Fewer dental problems with pregnancy 8X less diabetes 4X fewer C-sections (>37 ng) 4X less preeclampsia (40 ng vs 10 ng) 5X less child asthma 2X fewer language problems age 5 | 42 ng/ml | Desirable | < 750 mg | $1 |
4000 | 2X fewer pregnancy complications 2X fewer pre-term births | 49 ng/ml | Should have cofactors | < 750 mg | $3 |
6000 | Probable: larger benefits for above items Just enough D for breastfed infant More maternal and infant weight | Should have cofactors | < 750 mg | $4 |