What is the ruling on a wife preventing pregnancy, with the husband's knowledge and consent, if pregnancy causes her extreme hardship and difficulty, knowing that the husband desires to have children?

If a woman is harmed by pregnancy, a harm that is significant and confirmed by a knowledgeable and trustworthy doctor, then it is permissible for her to avoid conception, and her husband does not have the right to compel her, because causing harm is forbidden in Islamic law. However, if the harm is merely a usual hardship, then it is not permissible for her to avoid conception.