Is a woman sinful for having discarded a dead fetus she miscarried while young and ignorant, and what should she do now, forty years after the incident?

It is not permissible to dispose of a fetus without burial. The woman should have buried her miscarried fetus. If she did not, she must repent, seek forgiveness, and perform good deeds. If the miscarriage was not due to her actions, then there is nothing upon her. However, if it was due to her actions, then in addition to repentance, she must pay a ghurrah (one-tenth of her blood money), because the abortion occurred after the stage of formation, which necessitates blood money (diyah) and expiation (kaffarah). The diyah is five camels or their value, to be given to the heirs of the fetus, unless they waive it. She does not inherit anything from it.