What is the ruling of the Shari'ah on using an intrauterine device (IUD) to prevent pregnancy, and what is the ruling on prayer throughout the duration of the menstrual cycle in the event of its insertion?

It is forbidden to insert an IUD except out of dire necessity or urgent need, because it requires the uncovering of major awrah (private parts), even if the one uncovering is a female doctor, and because of the menstrual cycle disturbances it causes.

If the IUD was inserted out of necessity and did not alter the menstrual cycle, the ruling remains as it was. However, if it altered it, then any bleeding beyond the usual menstrual period is considered istihadah (non-menstrual vaginal bleeding), and she should pray and fast after performing ghusl (ritual bath) and wudu (ablution) for each prayer.

As for insertion without necessity, if it does not alter the cycle, it is permissible to keep it. But if it alters it, then it must be removed.

It is permissible for a woman to insert the IUD herself or through her husband if it does not cause a disturbance in the cycle, even if there is no necessity, because it is similar to the permissible method of azl (coitus interruptus) with the consent of both parties.

If the excess bleeding, beyond the usual, changes in color and odor because of it, then it is considered istihadah blood, even if it does not exceed 15 days. The more cautious approach is to observe purity, prayer, and fasting with it, while avoiding intercourse if possible.