Nitrous Oxide for Pain Management of Intrauterine Device (IUD) Insertion

Long acting reversible contraception (LARC) including the IUD provides several advantages that may be attractive to women. These include non-daily use, rapid reversibility and low failure rates. The American College of Obstetricians and Gynecologists (ACOG) endorses the use of IUDs among adolescents and nulliparous women, dispelling the myth that IUD use is contraindicated in this population.

Rates of IUD uptake among nulliparous women have not been reported. There are some barriers that may help explain the low uptake of IUDs by teens and nulliparous women, including fear of pain during IUD insertion. This concern is also voiced by providers who perceive pain with IUD insertion to be higher among nulliparous women (Allen, Goldberg et al. 2009).

There is limited evidence comparing subjective pain scores with IUD insertion between nulliparous versus parous women. However, there have been a number of studies evaluating the efficacy of misoprostol, non steroidal anti-inflammatory drugs and local anesthesia in reducing pain during IUD insertion. These included comparisons of pain scores between both nulliparous and multiparous women and reported pain scores by group. These studies have failed to demonstrate evidence that any of the aforementioned interventions significantly reduce pain scores compared to placebo (Allen et al. 2009). We conclude that pain with IUD insertion among nulliparous and adolescent women is within the high range of pain scale measurement standards. Therefore, further investigations of optimizing pain management during this procedure are warranted in order to lead to increased acceptability and adoption of IUDs among this population of women.

Nitrous oxide (NO) is an inhaled gas administered with oxygen in a fixed ratio for analgesia and sedation. It has been used for many years for procedural analgesia and anesthesia in outpatient settings and it reduces anxiety, the perception of pain and alters consciousness. It is attractive for the clinic setting as it demonstrates rapid induction and rapid resolution, allows for patient control of use, exhibits few side effects and boasts a benign safety profile in the setting of scavenging systems and open air clinics. Furthermore, NO systems are relatively inexpensive and noninvasive.

For all these reasons, NO seems to be an ideal approach for pain management with IUD insertion for nulliparous women. No studies have investigated the use of NO in this context. The aim of our study is to objectively identify pain reduction scores and satisfaction with NO use compared to typical insertion practices during IUD insertion for nulliparous women.

Inclusion criteria

• Age >18 OR between the ages of 12-17 with a parent/legal guardian who can consent
• English speaking
• Desires a Mirena® or ParaGard® IUD
• Nulliparous woman
• Can use laughing gas
• Has not taken narcotic pain medications prior to procedure

Exclusion criteria

• Currently pregnant
• If you have been pregnant before, pregnancy lasting longer than 19 weeks, 6 days
• Less than 4 weeks have elapsed from the end of a spontaneous abortion or medical abortion.
• Desires Skyla® IUD
• Pelvic Inflammatory Disease in the last 3 months
• Current mucopurulent discharge
• Uterine anomaly that distorts the uterine cavity
• Known uterine fibroid with disruption of the uterine cavity
• Copper allergy/Wilson's disease (for ParaGard®)
• Current cervical or uterine cancer
• Inability to breathe through the nose
• Significant active upper airway infection