The following is from the book "Fasting and Eating for Health" by Joel Fuhrman, M.D.
"In cases in which hormone replacement is essential for instance, with panhypopituitarism or hypothyroidism, administration of the appropriate hormone(s) may be continued during the fast. However, blood parameters should be observed and the medication dose lowered accordingly, because these patients generally require much less medication during the fast than when eating."
I would also think taking birth control while fasting would make you feel sick or sicker.
He also states: "Clearly a list can be made of hundreds of medications that should not be combined with therapeutic fasting. It would be inappropriate to compile such a list here. Suffice it to say that except in rare instance, a patient should be stable enough to be able to stop all medication either before a fast or within a few days after the fast has begun, or a fast should not be entertained."
"Vitamin Supplementation During a Fast"
"Vitamin deficiency attributed to fasting is exceedingly rare. It normally doesn't occur on fasts less than 45 days in length unless the individual was depleted at the onset of the fast. Taking vitamins during a fast is unnecessary and can create unpleasant symptoms."
Hope this helps you...Wishing you a successful fast!