What about if the menses come during a fasting day, does the woman have to continue fasting ? Also, what happens if the menses of a woman stops during a day of fasting, what she should do?
If the menses come during a fasting day, she has to break her fasting right away and must eat. It is haram to fast even one minute. Additionally, she must repeat the fasting day.
If the menestruation stops during a fasting day, she should take a shower (gusulh) and stop eating until Magrib and repeat the fasting day.
Allah knows best.
Imam of Masjid Manhattan