A recent clinical trial concluded that vitamin D supplementation during pregnancy and infancy may prevent allergies. In addition, the researchers found that vitamin D supplementation reduced the proportion of children who made trips to the doctor for asthma.
Medical Xpress recently covered the study in an article. Click here to read.
This study on VitaminDWiki has the following title
Five times less mite allergy when vitamin D added in mid pregnancy and to infant – RCT April 2016
There are ~ 30 other similar studies there. Higher vitamin D doses and vitamin D given earlier would most likely provide 10X or perhaps 15X better response.
http://vitamindwiki.com/tiki-index.php?page_id=7454