Intrauterine Devices

The aim of this study is to determine if 3ml of inhaled Methoxyflurane, in the form of a Penthrox inhaler, reduces pain during IUD insertion and/or endometrial biopsy. The proposed study is a double-blind, placebo-controlled RCT. Each participant will be randomly assigned to one of two arms: 1. Intervention (3ml of Methoxyflurane via a Penthrox inhaler) 2. Placebo (3ml of normal saline via an identical placebo Penthrox inhaler) The primary outcome is global pain score, which will be patient-reported by the 100 mm Visual Analogue Scale (VAS) 5-minutes following the procedure (endometrial biopsy or IUD insertion).