What Is The Use Of Susten?

i have pcos, my first iui failed , i am know taking vitamin tablets and for five days i took fertolet from my 3rd day of periods and from the 16th day of the period i have to take susten vt 200. i want to know the use of susten vt 200 , is there a chance of pregnancy with this medication, earlier i took susten orally but now it is vaginal insert what is the difference and benefit from the taking it through vaginal