A woman who misses fasting due to postpartum recovery (nifās) and breastfeeding falls under those who are excused in the Sharīʿah. Allah says: “And whoever is ill or on a journey, then an equal number of other days.” (2:185). Scholars include postpartum bleeding and legitimate health concerns under this general principle of excuse.

After nifās ends, if a woman continues not to fast due to breastfeeding and there is a reasonable fear of harm, either to herself or to her child, then she is also excused from fasting.

The scholars differed regarding what is required afterward. The Hanafi school holds that in such cases, only making up the missed fasts (qaḍā’) is required, and no fidyah is due. This is because the woman is considered temporarily unable, similar to a sick person, and Allah only obligated making up the missed days.

The majority of scholars (Maliki, Shāfiʿi, and Hanbali) make a distinction. If the mother did not fast out of fear for her own health, then only qaḍā’ is required. However, if she did not fast out of fear for her child (such as concern about milk supply or the child’s well-being), then they require both qaḍā’ and fidyah (feeding a poor person for each missed day).

The stronger and more broadly applicable opinion, especially in cases where the mother’s own recovery and health are also involved, as in your situation, being only 3 weeks postpartum, is that you are excused and only required to make up the missed fasts. Postpartum recovery itself is a clear and valid excuse, and breastfeeding concerns are closely tied to the mother’s health as well.

Therefore, you should make up the missed fasts when you are able, at a time when fasting does not harm you or your child. You do not need to pay fidyah according to the stronger opinion. However, if you wish to give charity in addition, it is a good and rewarding act.

Allah says: “Allah intends for you ease and does not intend for you hardship.” (2:185)