Vitamin D Supplementation During Pregnancy May Reduce Risk of Atopic Eczema Among Infants

In this video, Sarah El-Heis, MRCP, DM, lead author of the study, "Maternal Antenatal Vitamin D Supplementation and Offspring Risk of Atopic Eczema in the First 4 Years of Life: Evidence from a Randomized Controlled Trial" describes how her research team found a reduced risk of eczema at the age of one in those infants whose mothers had vitamin D supplementation. She also discusses whether there were similar findings at different ages, and whether breastfeeding plays a role in the protective effects associated with vitamin D supplementation.

Additional Resource:

  • El-Heis S, D'Angelo S, Curtis EM, et al. Maternal antenatal vitamin D supplementation and offspring risk of atopic eczema in the first 4 years of life: evidence from a randomized controlled trial. Br J Dermatol. 2022;187(5):659-666. doi: 10.1111/bjd.21721.

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Sarah El-Heis MRCP, DM

My name is Sarah El-Heis. I am an associate professor of dermatology. I'm also an honorary consultant dermatologist at the University Hospital of Southampton.

What was the impetus for this study? Why now?

So we've known for a while that atopic eczema is a highly prevalent condition and it significantly impacts the quality of life of those that are affected and impacts the health services. So far, there have been a few observational studies that have led to speculation that vitamin D supplementation in the antenatal period may be beneficial, but there are no current proven general population preventive strategies until now.

How does this study fill a gap in our knowledge?

Our data came from the MAVIDOS Study, which is a large multicenter trial that involved pregnant women who were randomized to receiving 1000 international units of vitamin D supplement, or a matched placebo, from 14 weeks of their gestation. And then we examined the children for their eczema at ages 1, 2, and 4 years. And what we actually showed was that there was a reduced risk of eczema at the age of 1 in those infants whose mothers had the vitamin D supplementation. There were similar findings at ages 2 and 4, but the association was weaker. But the really other interesting thing was that protective effects of the maternal vitamin D supplementation was only significant in those infants who were breastfed for more than one month.

What are the gaps in our knowledge that remain following the publication of your study?

We still don't know the exact mechanisms by which maternal vitamin D supplementation can impact the infant risk of eczema, but our data has shown that breastfeeding may be one of those mechanisms. So perhaps it's by increasing the vitamin D content in the breast milk that the infant is getting more vitamin D through that way. The other thing is that there's a lot of evidence coming out in regards to vitamin D influencing the gut microbiome, which we know in itself can impact the risk of eczema. So breast milk and microbiome are the hot topics for us.

What methodologies would you use for future studies examining the association between vitamin D and the gut microbiome and breast milk?

We're quite lucky in our center, we have access to a number of large cohort studies, some of which we have collected breast milk from, and ascertained atopic eczema in the infants. So we don't have breast milk data from the MAVIDOS Study, but we do have it from other studies, so we could get the data and the analysis done from other cohorts.

Beyond dermatologists, what other specialists would be interested in the results of this study?

Dermatologists and pediatricians have found this really interesting, but also primary care physicians and all the maternity care providers, so obstetricians, midwives, as well as nutritionists and dieticians. So far, we've had people reach out to us from all these fields commenting on our paper, mainly because they've all witnessed the impact that atopic eczema can have on effectively the individuals, their families, and the healthcare system. And until now there isn't any guidance as to what advice they could be giving to prevent eczema developing in unborn children.

What were some of the comments from other specialists interested in your study?

Some were about the doses that we've used. So in this study, we used a thousand international units, which is slightly higher than the recommended vitamin D supplementation, at least in the UK, but we know it is a safe dose to use in pregnancy. So one question was about the dose. The other thing is the timing of starting the supplementation. So obviously we started it quite early on in pregnancy, but there is an indication towards perhaps even starting at preconception might be even more beneficial. It helps build up the vitamin D levels in the mothers.

What were the main takeaways from your study?

The main takeaway would probably be that we've shown that maternal vitamin D supplementation can reduce the risk of eczema in infants, and particularly in those who've breastfed for more than 1 month.