Is a vitamin d reading of 4.2 in a woman aged 35 normal ?

You are deficient: Optimal level for Vit D is over 40 ng/dl. I recommend 10,000 IU of D3 daily for several months, and re-check. Adjust your dose as appropriate. May require more than 5,000 IUs per day thereafter. Figure illustrates the unadjusted relationship between pre-operative 25(OH)D levels and the composite outcome parameter MACCE (major adverse cardiac and cerebrovascular events). (4 ng/dl = 10 nmol/l)