Shortly before Ramadan, I changed the kind of contraceptive pills that I take. This caused a light bleeding that kept on during most of Ramadan. I wanted to fast the six days of Shawwal. I first observed the number of the normal days that regularly make up my menstrual period and then observed the six days of Shawwal. Is this enough?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

If this bleeding could be menses because it comes out during the period in which menses is expected to happen; i.e. the bleeding happens 15 days after the expiry of the last menstrual period, then this bleeding is considered to be menses. The Muslim scholars disagree on whether only the number of the days of the last menstrual period should count as menses and the rest of the bleeding counts as istihadhah (vaginal bleeding outside the menstrual period) unless it recurs, or the entire period of bleeding shall count as menses unless it exceeds 15 days.  

Based on the two viewpoints, the number of the regular days of menses during the bleeding period shall be considered as menses. Therefore, the fasting that is missed in this period must be made up because it took place in the period in which menses regularly occur. What the questioner has done is valid according to the scholarly agreement; that is, to make up the days of fasting that she missed during her regular period. According to Hanbali scholars, this is also the sound opinion unless the bleeding continuously recurs and it does not exceed the regular days of menses for three times.

Allah knows best.