ADO.NET :: Use Date Data Type In While Loop?

i have an apllication which calculates date. First i retrieved initial date and expiry date from the database using datareader. then i want to check whether initial date is less than or equal to expiry date.If it satisfies the condition I want to add one month to that date(eg: if initial date is 09/10/2010 and expiry date is 09/08/2011 if looping statement becomes true initial date should be incremented by one month i.e. 09/11/2010(dd/mm/yyyy))

how can I do this using any looping statements. I tried like this

While CDate(indate) <= CDate(expdate)
nextindate = CDate(indate.AddMonths(1))
End While