What is the Sharia ruling on a wife's refusal to conceive from her husband, under the pretext of her illness and inability to do so, given that she is 39 years old and they already have two daughters, despite doctors confirming that her illness would not affect pregnancy?

Procreation is a shared right between spouses, so it is not permissible for the wife to refuse it unless there is clear harm or with the husband's consent. Temporary birth control is permissible to space out pregnancies or to stop them for a certain period due to a legitimate need, with the agreement of both spouses, provided that it does not result in harm, that the method is lawful, and that it does not involve aggression against an existing pregnancy.