RESUMEN
PURPOSE: This study aimed to assess the pain scores at the insertion of the 52 mg levonorgestrel-releasing intrauterine system (LNG-IUS) among nulligravidas, parous women with previous vaginal delivery and parous women with elective caesarean-delivery without any previous labour or cervix dilation. MATERIALS AND METHODS: The present research is a prospective, single-cohort study that included 413 women aged 15-49 years who opted for LNG-IUS placement for contraception or treatment of heavy menstrual bleeding. Women who participated in the present study were not submitted to any pharmacological pain-relieving intervention to perform the procedure. Pain at insertion was evaluated by using a Visual Analogue Scale (VAS). Pain was classified as absent (0), mild (1-3), moderate (4-6), or severe (7-10). The women were divided as: (1) nulligravidas, (2) parous women with a previous vaginal delivery, or (3) parous women with elective caesarean-delivery without any previous labour or cervix dilation. RESULTS: Nulligravidas women presented a higher mean pain score, when compared to women with elective caesarean-delivery and women with previous vaginal delivery (6.6 ± 2.0 vs 5.5 ± 2.1 and 3.9 ± 2.4, respectively; p < 0.001). Nulligravidas and women with elective caesarean-delivery were more likely to have pain classified as moderate or severe (in relation to absent or mild) than women with previous vaginal delivery (p < 0.001). Multiple Linear Regression Analysis demonstrated that 29.5% of all variability of the pain score was explained by two predictor/independent variables: nulligravidas or women with elective caesarean and difficulty at IUD insertion. CONCLUSIONS: Women with previous vaginal delivery had lower pain scores at LNG-IUS insertion when compared to nulligravidas and women with elective caesarean-delivery without any previous labour.