Objectives Many factors are suspected to influence the intrauterine device (IUD) insertion process. This study sought to examine the effects of a few key variables on IUD insertion tolerability, complications and follow-up issues.

Methods A retrospective chart review was undertaken of all IUD insertions over an 11-month period at an urban Canadian women's clinic. Linear regression analysis of 354 insertions assessed the effects of parity, age, local anaesthesia and other variables on insertion pain. Chi square (χ²) and analysis of variance statistics were employed to evaluate differences in insertion complications by parity and age. A χ² test was performed to compare follow-up expulsion or removal rates by parity.

Results Statistically significant differences were found, with nulliparous women and those who received local anaesthesia reporting more insertion pain. Age, IUD type and recent abortion status did not affect insertion pain. Nulliparous women did not experience significantly more insertion difficulty or complications, nor did they have higher rates of expulsion or removal at follow-up.

Conclusions These findings suggest that the practice of providing cervical anaesthesia at IUD insertion may cause slightly more pain, without any obvious additional benefit. The difference in insertion pain by parity, although statistically significant, is small enough to be of questionable clinical importance. Overall, these findings add to the growing body of evidence for IUDs being safe and well-tolerated in nulliparous women.