Timing of insertion of levonorgestrel-releasing intrauterine system: a randomised controlled trial

Objective The objective was to assess whether patient-perceived pain during the insertion of the levonorgestrel-releasing intrauterine system (LNG-IUS) depends on the timing during the menstrual cycle.

Design A stratified two-armed non-inferiority randomised controlled trial.

Setting Large teaching hospital in Veldhoven, the Netherlands.

Sample From October 2013 to May 2014, 60 nulliparous and 60 multiparous women were randomised. Eight women withdrew after randomisation and before insertion took place: therefore, data from 112 women were collected and analysed.

Methods Women were randomised to the groups `during menstruation' (i.e. days 1-7 of menstruation) or `outside menstruation' (i.e. any day of the cycle after menstruation without the presence of vaginal blood loss) in a ratio of 1 : 1.

Main outcome measures The primary outcome was pain during insertion, measured by the visual analogue scale (VAS, 0100 mm). Second, we analysed ease of insertion, bleeding pattern, satisfaction, pregnancy, and expulsion rate. The follow-up time was 3 months.

Results The mean VAS score for nulliparous women was 74 mm (95% confidence interval, 95% CI 67-81) in the `during menstruation' group, compared with 66 mm (95% CI 59-74) in the `outside menstruation' group (P = 0.14). The mean VAS score for multiparous women was 30 mm (95% CI 20-40) in the `during menstruation group', compared with 43 mm (95% CI 32-53) in the `outside menstruation' group (P = 0.08). There was no difference between the stratified `during menstruation' group and the `outside menstruation' group with regards to ease of insertion, satisfaction, bleeding pattern, and median spotting and bleeding days for the use of the LNG-IUS 3 months after insertion.

Conclusions As we did not find that the level of pain perceived during insertion was higher during menstruation, compared with outside menstruation, we conclude that the LNG-IUS can be inserted at any time during the menstrual cycle, especially in the case of nulliparous women.