ANSWER:

No, you’re not sinful if you break these Sunnah fasts. 

The prophet(saw) would fast on Thursday and monday. what would happen if I break my fast am i sinful? And likewise the fasts he would keep on other times which are not compulsory if I break those am i sinful? What is the recompense if i have committed this sin.

Fasting | January 13, 2019 5:05 pm
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I read some other scholar about missed fasts when you miss your fasts due to pregnancy,,, you can only give fidya you don’t need to make up your pregnancy missed fasts. Is it true?
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My maa has died out of cancer in 2014.She was a fourth stage cancer patient with kidney problem.Whatever she would eat,used to vomit.She was under treatment then nd i cant remember wheather doctor has told her to abstain from fasting in Ramadan or not.Should I have to fast on her behalf?