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Evidence ‘inconclusive’ for benefits of vitamin D in pregnancy, study finds

The evidence for vitamin D reducing the likelihood of gestational diabetes and preeclampsia is ‘inconclusive’ according to a new study.

The study suggests that the evidence for recommending vitamin D supplements to pregnant women is weak and that supplementation may not reduce the risk of adverse outcomes in pregnancy.

The study, carried out by an international team of researchers, looked at just under 7,400 women using data from two European pregnancy studies. Researchers looked at their antenatal vitamin D levels and also looked at the genetic variations that the women had that were associated with vitamin D production.

They found no strong evidence of a causal association between vitamin D levels and gestational hypertension, and only weak evidence of an association between vitamin D levels and preeclampsia.

They also found no consistent evidence of an association between the genetic variations and gestational hypertension and preeclampsia.

The authors said in the paper: ‘According to the World Health Organization, evidence recommending vitamin D supplementation for women during pregnancy to reduce adverse pregnancy outcomes is insufficient.

‘Our findings support the current WHO position.’

NICE currently suggests that GPs recommend vitamin D supplements at first contacts with all pregnant women.

BMJ 2018; available 21st June 

Readers' comments (5)

  • Vinci Ho

    You see
    This is another evidence to baffle the whole concept of screening Vitamin D and treating insufficiency and deficiency ; supplementing elderly and in pregnancy.
    The conundrum question , ‘ what the hell is really going to happen if vitamin D is that low?’ , is never being answered . Yes , we have not enough sunlight exposure in this country perhaps , but what about those countries situating further towards the two poles ?
    I know some dermatology colleagues are extremely keen on vitamin D in pathogenesis of some skin conditions, but have we swung the pendulum too far to one extreme in terms of the number of vitamin D prescriptions we issue everyday in NHS??

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  • I always thought lab values were declared abnormal on their basis of deviation from the population average.

    So I have never understood how it can be meaningful to say that over 50% of UK adults have insufficient vitamin D.

    To me that is just another way of saying that the reference range for UK adults is wrong.

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  • Never seen vitamin D supplements improve joint pains or tiredness. Rheumatologists seem obsessed!

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  • The whole vitamin d thing is a complete con and overdiagnosis at it's very worst - it makes me shudder to think of all the wasted money, time and consultations on this unproven rubbish. The reference ranges for a starter are completely wrong. True severe deficiency (

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  • Dylan. Nail. Head.

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