Is it permissible to use an IUD to prevent pregnancy?

The insertion of an IUD is permissible under two conditions: that it does not harm the woman, and that her husband grants permission for it. Nevertheless, a woman should not prevent pregnancy, as a large progeny brings about immense benefits, unless she is physically weak and fears harm from repeated pregnancies. In such a case, she is excused, provided her husband permits it and the contraceptive method itself causes no harm.