The effect of vitamin D replacement therapy on insulin resistance and androgen levels in women with polycystic ovary syndrome. In conclusion, women with PCOS have mostly insufficient vitamin D levels, and vitamin D replacement therapy may have a beneficial effect on IR in obese women with PCOS.
remember such is the prevalence of Vitamin D deficiency that one does not have to wait for a 25(OH)D test before supplementing with 1000iu/daily for each 25lbs you weigh.
Supplementing with up to 10,000iu/daily is safe even in places where regular sun exposure is a practical possibility.
It takes roughly 3 months using an effective amount daily to achieve a stable level around 60ng/ml and a 25(OH)D test at that point will indicate if more is required or not. Remember human breast only produce vitamin D 3 milk when 25(OH)D levels are around 60ng/ml and at latitude 32n it takes around 6400iu/daily to ensure this happens. Further north will require more particularly in winter.

Don't forget that increasing Vitamin D allows your body to absorb more calcium from diet so supplementing with calcium should NOT be necessary but more magnesium and Vitamin K may be useful to transport and fix that extra calcium in bones as required.