All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
Menses does not interrupt the continuity of fasting. If a woman is obliged to fast for two consecutive months, then she should count the numbers of days she fasted before menses and then continues the count and fasting after she becomes pure.
Al-Buhooti [from the Hanbali school] said: 'The continuity should be observed, but if it is interrupted by Ramadan, or 'Eed when one is obliged to break the fast, or when a woman is in menses or has postpartum bleeding, then this is not considered as a discontinuity in fasting.'
Allaah Knows best.