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Pregnancies helped by Vitamin D – recommendations and trials underway – review Dec 2017

Vitamin D supplementation during pregnancy: state of the evidence from a systematic review of randomised trials

the bmj | BM/2017;359:j5237 | doi: 10.1136/bmj.j5237
Daniel E Roth,1,2,3 Michael Leung,2 Elnathan Mesfin,2 Huma Qamar,2,3 Jessica Watterworth,2,3 Eszter Papp2
1 department of Paediatrics, Hospital for Sick Children and University of Toronto, Toronto, ON, Canada
2 Centre for Global Child Health and SickKids Research Institute, Hospital for Sick Children, Toronto, ON, Canada Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
Correspondence to: D E Roth daniel.roth at sickkids.ca

  • Yet another review/meta-analysis which ignores the dose size used
  • The same importance is given to 400 IU daily as 6,000 IU daily
  • So, since most of the studies give only 400 IU, the great benefits of studies giving >4,000 IU remain hidden
  • Surprisingly the vast majority of all studies (even with small doses) found an increase in birth weight - see chart below)

Based on good studies ignored by this review VitaminDWiki recommends a minimum of 4,000 IU during pregnancy

Healthy pregnancies need lots of vitamin D > 4,000 IU

1. Miscarriage 2.5 times Observe
2. Pre-eclampsia 3.6 timesRCT*
3. Gestational Diabetes 3 times RCT*
4. Good 2nd trimester sleep quality 3.5 times Observe
5. Premature birth 2 times RCT*
6. C-section - unplanned 1.6 timesObserve
7. Depression AFTER pregnancy 1.4 times RCT*
8. Small for Gestational Age 1.6 times meta-analysis
9. Infant height, weight, head size
     within normal limits
10. Childhood Wheezing 1.3 times RCT*
11. Additional child is Autistic 4 times Intervention
12.Young adult Multiple Sclerosis 1.9 timesObserve
13. Preeclampsia in young adult 3.5 timesRCT*
14. Good motor skills @ age 31.4 times Observe
15. Childhood Mite allergy 5 times RCT*
16. Childhood Respiratory Tract visits 2.5 times RCT*

Pregnancy category starts with

587 items in Pregnancy category

 - see also


  • Click on chart for details


  • Numerous randomised trials and systematic reviews of vitamin D supplementation during pregnancy have been published, with conflicting results and conclusions
  • Recommendations regarding vitamin D supplementation vary widely among medical and professional organisations, and WHO currently recommends against routine prenatal vitamin D supplementation


  • Systematic review and meta-analyses of 43 trials including 8406 participants showed that prenatal vitamin D supplementation was associated with increased maternal and cord serum 25-hydroxyvitamin D concentrations, increased mean birth weight, reduced the risk of small for gestational age, reduced the risk of wheeze in offspring, and increased infant length at one year of age There was a lack of evidence of benefits of prenatal vitamin D supplementation for maternal health conditions related to pregnancy, no effect on other birth outcomes of public health importance such as preterm birth, and scant evidence on safety outcomes
  • Few of the trials were designed to test the effect of vitamin D on clinical or functional outcomes, and most trials were small and at overall high or uncertain risk of bias
  • Thirty five planned or ongoing prenatal vitamin D trials could contribute an additional 12 530 participants to future systematic reviews

Increasing number of studies and participating mothers


To estimate the effects of vitamin D supplementation during pregnancy on 11 maternal and 27 neonatal/ infant outcomes; to determine frequencies at which trial outcome data were missing, unreported, or inconsistently reported; and to project the potential contributions of registered ongoing or planned trials.

DESIGN Systematic review and meta-analysis of randomised controlled trials; systematic review of registered but unpublished trials.

Medline, Embase, PubMed, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials from inception to September 2017; manual searches of reference lists of systematic reviews identified in the electronic search; and online trial registries for unpublished, ongoing, or planned trials.

Trials of prenatal vitamin D supplementation with randomised allocation and control groups administered placebo, no vitamin D, or vitamin D <600 IU/day (or its equivalent), and published in a peer reviewed journal.

43 trials (8406 participants) were eligible for meta-analyses. Median sample size was 133 participants. Vitamin D increased maternal/cord serum concentration of 25-hydroxyvitamin D, but the dose-response effect was weak. Maternal clinical outcomes were rarely ascertained or reported, but available data did not provide evidence of benefits. Overall, vitamin D increased mean birth weight of 58.33 g (95% confidence interval 18.88 g to 97.78 g; 37 comparisons) and reduced the risk of small for gestational age births (risk ratio 0.60, 95% confidence interval 0.40 to 0.90; seven comparisons), but findings were not robust in sensitivity and subgroup analyses. There was no effect on preterm birth (1.0, 0.77 to 1.30; 15 comparisons). There was strong evidence that prenatal vitamin D reduced the risk of offspring wheeze by age 3 years (0.81, 0.67 to 0.98; two comparisons). For most outcomes, meta-analyses included data from a minority of trials. Only eight of 43 trials (19%) had an overall low risk of bias. Thirty five planned/ongoing randomised controlled trials could contribute 12 530 additional participants to future reviews.

Most trials on prenatal vitamin D published by September 2017 were small and of low quality.
The evidence to date seems insufficient to guide clinical or policy recommendations. Future trials should be designed and powered to examine clinical endpoints, including maternal conditions related to pregnancy (such as pre-eclampsia), infant growth, and respiratory outcomes.


 Download the main PDF from VitaminDWiki

Vitamin D recommendations for pregnancies

Canadian Paediatric Society 2000 IU
Indian – govt 400 IU – if have little access to sunlight
Canada – HealthDrink milk, and 600 IU (IoM)
US Institute of Medicine 600 IU
US American College of
Obstetricians and Gynecologists
1,000-2,000 IU
US Endocrine Society 1500 IU only if at risk for Vitamin D deficiency
Australia 200 IU if have minimal access to sunlight
European Food Safety Authority 600 IU
UK Scientific Advisory Committee
on Nutrition (SCAN)
400 IU
World Health Organization 0 – is not recommended

Condensed from Data Supplement     Recommendations

Data supplements

1: Selected recent recommendations for vitamin D intake or supplementation in pregnancy
    Download the PDF from VitaminDWiki
2: Search strategies for electronic databases
3: Outcome variable case definitions and methods of ascertainment criteria
4: Search strategy for clinical trial registries
5: Studies included in systematic review and eligible for inclusion in meta-analyses
6: Contributions of prenatal vitamin D trials to meta-analyses
    Download the PDF from VitaminDWiki
7: Unpublished outcome data and clarifications of published findings
8: Prenatal prospective controlled vitamin D supplementation trials ineligible for inclusion in meta-analyses
    Download the PDF from VitaminDWiki
9: Risk of bias for trials eligible for inclusion

Birth weight increased in RCT using any amount of vitamin D

Suspect that only 2 trials which found a weight loss were those (1986) which used vitamin D2

4,000 IU placebo?


Created by admin. Last Modification: Thursday January 25, 2018 16:38:44 UTC by admin. (Version 16)

Attached files

ID Name Comment Uploaded Size Downloads
9095 Placebo.jpg admin 02 Jan, 2018 03:44 26.14 Kb 14
9094 Pregnancy reccommendations.pdf admin 02 Jan, 2018 00:27 167.49 Kb 19
9093 Study vs problem matrix.pdf admin 02 Jan, 2018 00:20 146.10 Kb 18
9092 Birth weight.jpg admin 02 Jan, 2018 00:03 57.86 Kb 17
9091 Pregnancy and Vitamin D studies.jpg admin 01 Jan, 2018 23:46 21.52 Kb 18
9090 Pregnancy review of RCT.pdf admin 01 Jan, 2018 23:45 715.63 Kb 12
9089 Trials included.pdf admin 01 Jan, 2018 23:44 436.50 Kb 16
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