FB 1.5

I am writing a stored proc where it is passed two dates, StartDate and
EndDate, and I need to iterate through each first day of the month
between the two dates:

CheckDate := StartDate;
while CheckDate < EndDate do
begin
...other SQL coding using CheckDate
CheckDate = get the next month, first day for CheckDate);
end;

Is there an easy way to do the CheckDate ?

Thanks,

Ed Dressel