Intrauterine Device Insertion Clinical Trials

Experimental: Intervention Group

Participants will receive a Penthrox inhaler containing 3 mL of methoxyflurane. Before speculum insertion, they will take intermittent inhalations every 30-60 seconds (6-10 breaths), following monograph instructions. They may continue self-administering the inhaler as needed during the procedure.~Participants will receive standard pain management prior to IUD insertion, which includes: 1) recommendation to use over-the-counter analgesics such as NSAIDs, and 2) the option to undergo a cervical block to minimize discomfort during the procedure.

Placebo_comparator: Placebo Group

Participants will receive an identical-looking inhaler containing 3 mL of normal saline. To maintain blinding, a drop of methoxyflurane will be placed on the outside of the device, which has no analgesic effect. Before speculum insertion, participants will take intermittent inhalations every 30-60 seconds (6-10 breaths), following monograph-style instructions, and may continue self-administering as needed during the procedure.~Participants will receive standard pain management prior to IUD insertion, which includes: 1) recommendation to use over-the-counter analgesics such as NSAIDs, and 2) the option to undergo a cervical block to minimize discomfort during the procedure.