Thanks for the query.
If your menses have been regular, then there is no possibility that you can get pregnant if you had intercourse during your menses. This is because its a fresh cycle and endometrium is shedding and hence even in cases of delayed ovulation in previous cycle, if fertilization takes place, it cannot implant on the shedding endometrium and hence can't get pregnant. Moreover fresh ovulation is due only after 10-12 days and hence in the absence of any ovulation, under normal situations, no amount of sperm ejaculated inside the vagina can cause any pregnancy. So you are completely safe.
I hope I have answered your query in detail.
Wishing you safe sexual practices.
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