Is it permissible for a wife to travel and abort her 17-week-old fetus without her husband's knowledge?

If a wife travels without her husband's permission, she is in error and disobedient (nashiz), and she must repent. If she aborts her fetus without a legitimate Shar'i (Islamic legal) excuse, she has committed a grave evil that necessitates repentance and the payment of the fetus's blood money (diyah), which is a "ghurrah" (one-tenth of the mother's blood money). Expiation (kaffarah) is also recommended. The husband's knowledge of the abortion does not alter its prohibition.