Effect of uterine sound on pain perception during intrauterine device insertion: A randomized trial.

Intrauterine devices (IUD) are among the most commonly used contraception methods owing to their effectiveness in providing reliable contraception, ease of application, non-obstruction of sexual life, affordability, minimal absolute contraindications, and reversibility. [ 1 ] Regarding the effectiveness of IUDs, recent meta-analyses reported that the overall pearl index was 0–1.4. [ 2 ] Hence, patient preference for using IUDs for contraception has increased over the years. [ 3 ] The utilization rate of IUDs in the United States has reached up to 17.8%, [ 4 ] while globally, this rate has been reported to be 15.5%. [ 5 ] Despite this increasing acceptance, a systematic Cochrane analysis conducted in 2015 revealed concerns regarding the use of levonorgestrel 52 mg IUDs and copper 380 mm 2 IUDs due to potential pain and fear of pain during insertion. [ 6 ] Therefore, comfort is a valuable goal for patients who choose IUD as a contraception method. Several studies have been conducted to prevent pain during IUD insertion, but most of the procedures employed caused only a moderate pain reduction. [ 5 ] Methods reported to reduce pain during IUD placement include cervical anesthetics, nonsteroidal anti-inflammatory drugs, and cervical priming agents such as dinoprostone or misoprostol. [ 6 ] In a meta-analysis, various drugs were compared to placebo using the visual analog scale (VAS) pain system during tenaculum placement and IUD insertion, as well as at 5–20 minutes after insertion. Lidocaine–prilocaine cream was found to be the most effective medication for pain associated with IUD insertion, whereas other medications were found to be ineffective compared to the placebo. [ 7 ] In addition to the medications investigated to reduce pain during IUD insertion, studies have been conducted on insertion techniques that can alleviate pain. [ 8 ] Two studies demonstrated that the use of uterine sounds during IUD placement can influence pain sensation. [ 9 , 10 ] However, Aissat et al could not demonstrate a statistically significant difference due to the small sample size. [ 10 ] Bastin et al included healthcare professionals who used only 1 of the 2 methods in their study, which led to bias in the analysis. [ 9 ] Further randomized studies with sufficient sample sizes resulting in significant findings are needed to advance research and knowledge accumulation in this field. This study aimed to compare pain scores between patients who underwent IUD insertion for contraception with the uterine sound method and those who underwent the procedure without the uterine sound method and obtain insights regarding which method is less painful.

Conceptualization: Mohammad İbrahim Halilzade, İnci Halilzade, Batuhan Turgay, Harun Kiliçkiran, Osman Türkmen, Müzeyyen Gülnur Özakşit. Data curation: Mohammad İbrahim Halilzade, Batuhan Turgay, Harun Kiliçkiran. Formal analysis: Mohammad İbrahim Halilzade, İnci Halilzade, Osman Türkmen. Funding acquisition: Mohammad İbrahim Halilzade, İnci Halilzade, Batuhan Turgay, Harun Kiliçkiran, Osman Türkmen, Müzeyyen Gülnur Özakşit. Investigation: Mohammad İbrahim Halilzade, İnci Halilzade, Osman Türkmen. Methodology: Mohammad İbrahim Halilzade, İnci Halilzade, Batuhan Turgay, Harun Kiliçkiran, Osman Türkmen, Müzeyyen Gülnur Özakşit. Project administration: Mohammad İbrahim Halilzade, İnci Halilzade, Batuhan Turgay, Harun Kiliçkiran, Osman Türkmen, Müzeyyen Gülnur Özakşit. Resources: Mohammad İbrahim Halilzade, İnci Halilzade, Batuhan Turgay, Harun Kiliçkiran, Osman Türkmen, Müzeyyen Gülnur Özakşit. Software: Mohammad İbrahim Halilzade, İnci Halilzade, Batuhan Turgay, Harun Kiliçkiran, Osman Türkmen, Müzeyyen Gülnur Özakşit. Supervision: Müzeyyen Gülnur Özakşit. Validation: Mohammad İbrahim Halilzade, İnci Halilzade, Batuhan Turgay, Harun Kiliçkiran, Osman Türkmen, Müzeyyen Gülnur Özakşit. Visualization: Mohammad İbrahim Halilzade, İnci Halilzade, Batuhan Turgay, Harun Kiliçkiran, Osman Türkmen, Müzeyyen Gülnur Özakşit. Writing – original draft: Mohammad İbrahim Halilzade, İnci Halilzade. Writing – review & editing: Mohammad İbrahim Halilzade, Batuhan Turgay, Osman Türkmen.

This randomized, controlled, single-blind clinical trial compared pain during IUD insertion with and without uterine sound placement techniques ( ClinicalTrials.gov identifier: NCT05956184 ; date of registration July 13, 2023). Participants who applied to Ankara City Hospital between July 2023 and September 2023 requesting an IUD for family planning were included in the study. Ethics committee approval was obtained from the Clinical Research Ethics Committee (No. 2 of Ankara City Hospital [21/712]). All participants signed informed consent forms before randomization. Participants with uterine leiomyoma, endometriosis, chronic pelvic pain, familial Mediterranean fever, chronically used analgesics, previously used an IUD for any reason, were nulliparous, or had uterine anomalies were excluded from the study because these conditions could potentially affect pain perception. Subsequently, the participants scheduled for IUD insertion were randomly classified into 2 groups: the uterine sound group and the without uterine sound group with parallel assignment. Based on participants’ preferences, they were administered levonorgestrel 52 mg IUDs or copper 380 mm 2 IUDs by 3 experienced operators trained in IUD insertion. A computer-generated sequence model was used for the randomization. Randomization was not stratified according to the IUD type. Participants were unaware of their groups. IUDs were inserted at least 6 months after each participant’s most recent childbirth. In the gynecological position, all participants underwent bimanual vaginal examination, uterine imaging, and uterine depth measurement using transvaginal ultrasound. Then, speculum was inserted, followed by disinfection of the cervix and vagina with betadine and the use of Pozzi tenaculum to immobilize the uterus. In 1 group, the IUD was inserted after entering the uterine cavity with uterine sounds. In the second group. The IUD was inserted directly without the use of uterine sounds. The strings were cut, and the Pozzi forceps and speculum were removed. In our clinic, the location of the IUD is confirmed using pelvic ultrasound. Participants who could not tolerate the examination or the tenaculum insertion, experienced complications during the procedure, and developed vasovagal reactions were excluded from the study. The main purpose of the study was to determine the difference in pain between the 2 methods during routine IUD insertion. However, complications such as vasovagal symptoms, uterine rupture, or failure to insert an IUD may cause differences in pain perception. At the end of the procedure, participants in both groups were asked to rate the most severe pain experienced during IUD insertion using the VAS (from 0 to 10); this was the primary endpoint of this study. All participants rested for 30 minutes after the procedure, and the pain experienced was evaluated again using the same scaling system; this was the secondary endpoint of the study. Participants’ age, body mass index, reproductive status, demographic characteristics and factors that may cause differences in pain perception during IUD insertion (parity, type of delivery (cesarean or vaginal), ultrasound findings (anteverted/retroverted uterus)) were recorded. Participants’ pain intensities were recorded as VAS score < 6 and VAS score ≥ 6, with VAS score ≥ 6 defined as high pain intensity and VAS score < 6 defined as low pain intensity. [ 11 ] Subsequently, to reveal high pain risk factors, all participants were reclassified into low- and high-pain groups, and their parameters were compared; this represented the third endpoint of the study. All data were collected by the principal investigator at the institution where the participants were treated. The principal investigator was blinded to the study groups. None of the participants used analgesics (such as nonsteroidal anti-inflammatory drugs) or cervical-ripening agents before or during the procedure. According to the sample size calculated using G Power 3.0.10 software, [ 10 ] with a power of 80%, effect size of 0.5, and alpha error of 0.5, the uterine sound group and the without uterine sound group required 64 participants each. All statistical analyses were performed using SPSS version 22 software (IBM Corp., Armonk). The normal distribution of data was examined using the Shapiro–Wilk test. Continuous and normally distributed variables are presented as mean ± standard deviation, and intragroup differences were assessed using Student t test. Continuous variables with non-normal distribution are presented as median (minimum–maximum), and differences between variables were analyzed using the Mann–Whitney U test. Categorical variables are shown as numbers (percentages), and differences between categorical data were compared using the chi-squared or Fisher exact test. Significant factors related to high pain perception during the procedure were investigated using multiple regression analysis. P  < .05 value was considered to indicate statistical significance.

Between July 2023 and September 2023, 189 participants requesting an IUD presented to our clinic. Twenty-three participants refused to participate in the study. Twenty-nine participants were excluded from the study because they experienced intense pain during preliminary preparation procedures for IUD insertion or had uterine leiomyoma or endometriosis. Five of the remaining 137 participants were excluded because of previous IUD use. Three participants were excluded because of vasovagal symptoms, and 1 was excluded because of IUD insertion failure. Finally, 128 participants were randomized for the study (Fig. 1 ). Of the 128 participants, 64 underwent IUD insertion with the uterine sound method, and 64 underwent the procedure without uterine sound. Participants ages ranged from 18 to 45 years. The demographic characteristics of the 2 groups are presented in Table 1 . No significant differences were found between the groups in terms of demographic characteristics. Demographical characteristics of the uterine sound and the without uterine sound groups. Data are presented as mean ± standard deviation (SD), median (minimum–maximum value), and number (%). BMI = body mass index, IUD = intrauterine device. Flow diagram. IUD = intrauterine device. When comparing the pain outcomes between the 2 groups, the incidence of high pain (≥6) during the procedure was higher in the without uterine sound group compared to the uterine sound group (32.8% vs 17.2%, P  = .041). However, there was no significant difference in the median pain scores during IUD insertion between the groups. Additionally, at 30 minutes after the procedure, the median pain score was higher in the without uterine sound group compared to that in the uterine sound group ( P  < .001). Contrastingly, the median pain scores during the procedure and the frequency of high pain at 30 minutes after the procedure were similar in both groups (Table 2 ). Pain outcomes of the uterine sound and without uterine sound groups. Data are presented as medians (minimum–maximum value) and numbers (%). Ankara City Hospital Obstetric and Gynecology Department, Family Planning Clinic, July 2023 and September 2023. VAS = visual analog scale. P < .05 was considered statistically significant. When participants were regrouped and compared based on the type of pain experienced during the procedure: low pain (VAS < 6) and high pain (VAS ≥ 6), 32 patients (25.0%) were in the high pain group, while 96 patients (75.0%) were in the low pain group. When the characteristics of these 2 groups were compared, the presence of a history of cesarean section, retroverted uterus, and frequency of nonuse of the uterine sound method were higher in the high pain group ( P  = .017, P  = .043, and P  = .041, respectively) (Table 3 ). Characteristics of the groups according to the severity of pain experienced during the procedure. Data are presented as medians (minimum–maximum value) and numbers (%). Ankara City Hospital Obstetric and Gynecology Department, Family Planning Clinic, July 2023 and September 2023. BMI = body mass index, IUD = intrauterine device, SD = standard deviation, VAS = visual analog scale. P < .05 was considered statistically significant. The significant factors identified for high pain experienced during the procedure were a history of cesarean section (OR = 2.70, 95% CI [1.14, 6.41], P  = .025) and the nonuse of the uterine sound method (OR = 2.54, 95% CI [1.06, 6.10], P  = .036). In the multiple regression analysis, these 2 factors were determined to be independent factors for severe pain during the procedure (Table 4 ). Results of the multiple regression analysis for the significant factors identified for high pain experienced during the procedure. CI = confidence interval, SE = standard error. P  < .05 was considered statistically significant. Ankara City Hospital Obstetric and Gynecology Department, Family Planning Clinic, July 2023 and September 2023.

This study aimed to investigate how the use of uterine sounds during IUD insertion affects pain scores. The incidence of severe pain during the procedure was higher in the group that did not use uterine sounds than in the group that did. Similarly, the median pain scores experienced 30 minutes after the procedure were higher in the without uterine sound group. Moreover, we found that a history of cesarean section and nonuse of the uterine sound method were independent risk factors for high pain during the uterine device placement. The use of IUDs for contraception has been a reliable method for several years. However, the pain experienced during IUD insertion leads to reservations when selecting this method. Almost all the patients experienced pain during IUD insertion. [ 12 ] Perceived pain varies depending on several factors. One study reported that participants with severe dysmenorrhea experienced more pain in all aspects of IUD insertion, including speculum and tenaculum placement than those with mild or no dysmenorrhea. [ 13 ] Birth history has also been shown to affect pain experienced during IUD insertion. One study demonstrated that nulliparity significantly increased pain perception, [ 14 ] while another found that nulliparous participants and those who had given birth via cesarean section experienced more pain than patients with a history of vaginal delivery. [ 15 ] Similarly, we found that participants with a history of cesarean section experienced higher levels of pain during IUD insertion. We believe that this is because the cervix of nulliparous participants and those who gave birth by cesarean section was less dilated than the cervix of those who gave birth vaginally. Several studies have evaluated the perceived pain during IUD placement in terms of medication types. [ 16 ] A study on analgesics found that prophylactic analgesia using 50 mg of tramadol and 550 mg of naproxen administered orally relieved pain during IUD insertion. However, tramadol capsules were more effective than naproxen tablets. [ 17 ] Another study reported that topical and local anesthetics are good options for reducing procedural pain in certain patients. [ 18 ] In addition to analgesics, medications that facilitate cervical preparation and dilation have been investigated. Rahman et al, in their meta-analysis of pain during IUD insertion, found that pharmacological methods such as lidocaine gel, lidocaine paracervical block, and a combination of lidocaine with diclofenac or prilocaine reduced pain scores at different time points during the procedure. The authors also reported that oral ketorolac and a combination of misoprostol and dinoprostone administered vaginally helped reduce pain. [ 19 ] Another study conducted with misoprostol demonstrated that misoprostol use before IUD insertion resulted in less pain and easier insertion. [ 20 ] However, in their analysis, Nguyen et al reported a lack of research on non-pharmacological interventions for managing anxiety and pain during IUD placement and conflicting evidence for pharmacological interventions. The authors highlighted the need for further research on non-pharmacological strategies for pain and anxiety management. [ 21 ] Additionally, a review published in 2024 comprehensively evaluated pain management options during IUD insertion in nulliparous women. They reported that cervical softening and dilation with dinoprostone 3 mg and misoprostol 3 mg reduced pain at all stages of IUD insertion and after insertion. The use of prostaglandins and 2% lidocaine gel was found to have the most clinically significant effects on pain control. [ 22 ] Aissat et al conducted a study comparing the level of pain experienced during IUD placement with and without uterine sound techniques. The uterine sound technique group consisted of 32 participants, whereas the non-uterine sound technique group included 28 participants. When these 2 groups were compared, the perceived pain during IUD placement was significantly lower in the group that did not use a uterine sound technique. [ 10 ] They concluded that the 1-shot direct-entry technique reduced expected pain. However, they did not reveal a statistically significant difference due to the small sample size. Contrarily, the number of participants in our study was sufficient to reveal a statistically significant difference, and we found that the perceived pain during the procedure was higher in the without uterine sound technique group compared to the uterine sound technique group. Bastin et al evaluated the difference in pain between these 2 methods and reported that patients who did not undergo the uterine sound technique experienced less pain. [ 9 ] However, they included healthcare professionals who used only 1 of the 2 methods to avoid overestimation in the without uterine sound group. This may have resulted in bias in the analysis. Based on studies demonstrating the reduction of pain through cervical dilation by the administration of dinoprostone and misoprostol prior to IUD insertion, [ 19 , 20 , 22 ] we believe that medical dilation performed before IUD placement has a similar effect as mechanical dilation with uterine sounds and, therefore, reduces pain. Additionally, we consider the conventional method to be superior to medical dilation in terms of not being administered by the patient (simultaneously) shortly before IUD placement (3 hours to 1 day) and not having potential side effects, such as fever. One limitation of our study was the exclusion of nulliparous participants. The reason for this is that nulliparous patients in our country generally do not prefer an IUD as a birth control method. Furthermore, it has been reported that the insertion of levonorgestrel 52 mg IUDs causes more pain than the insertion of copper 380 mm 2 IUDs. [ 15 , 23 ] However, due to the low number of participants who chose to receive T-shaped levonorgestrel-releasing IUDs, which is another limitation of our study, we could not make any inferences regarding the comparative effectiveness of these 2 types of IUDs. Other limitations include the increased use of ultrasound and the exclusion of patients with complications. Patients with complications such as uterine rupture were excluded because they may experience a higher pain intensity. Additionally, pain assessments were not performed for specific parts of the entire procedure, such as the preparation period before IUD insertion; thus, we focused specifically on pain during IUD insertion under normal conditions. The strengths of our study include an adequate number of participants, homogeneous distribution of groups, and consistent IUD placement technique by experienced and certified physicians.

IUDs are the preferred contraceptive method because of their effectiveness, reliability, and long-term use. However, minimizing the pain experienced during IUD insertion is crucial. IUD practitioners should apply the most painless and tolerable method for patients who choose an IUD for contraception. Based on our findings, we recommend the use of the uterine sound technique, as it is less painful than the non-uterine sound method. However, available scientific evidence regarding this topic is limited, and more studies are needed due to the inconsistencies in the available reports.