If only a woman in the shul is saying Kaddish, does she say it once or every time that the siddur says Kaddish yasom (the Kaddish for mourners)?
From this answer, I see that it is permitted for her to say kadish, according to R' Moshe.
But maybe it is only one kaddish and the obligation to say the rest of the kaddish yosom is not on the woman but on the congregation and there is no reason for her to say it.