All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is forbidden to put/use a loop unless there is a dire need that necessitates it, since such an action causes exposing the ‘Awrah (private parts) and preventing offspring, which is urged by the Law Maker (Allah and His Messenger).
Thus, if there is a need and one's goal of using the loop cannot be fulfilled through 'Azl (coitus interruptus) or contraceptive tablets, or unharmful chemical injection and so on, then there is no objection to use or put the loop. However, it should be put by a Muslim female doctor; if this is not available then by a non-Muslim female doctor; if it is not available then by a male Muslim doctor; if not available then by a non-Muslim doctor.
For more benefit on permanent birth control, please refer to Fatawa 119261, 83837, 134895, 87304, 87155, 89857 and 84086.
Allah knows best.