Swedish gynaecologists say that women who’ve never given birth find Intra Uterine Device (IUD) placement less painful when they use a local anaesthetic.
This September Karolinska affiliated researchers reported in the medical journal, JAMA, that a local anesthetic, Mepivacaine, could make IUD insertions more comfortable for women who have never given birth.
The researchers based at Danderyd Hospital, Dept of Obstetrics and Gynaecology in Stockholm tested whether Mepivacaine out performed a placebo in a triple blinded randomized controlled trial. They found that infusing 10 ml of 20 mg/ml of the numbing agent into the uterus made IUD insertion easier to tolerate than without any anaesthetic.
Limited Pain Relief Options For Women
Karolinska affiliated medics are on the hunt for effective pain relief for women. Currently there are few options for pain relief during outpatient gynaecological procedures. Part of the problem is that the clinical settings in which many of these procedures take place don’t allow for sedation. Women are expected to either endure, take an over-the-counter pain pill or if they are lucky, try a local anaesthetic.
In the past doctors have attempted pushing local anaesthetics through a tube through the opening of the cervix and into the uterus but very few drugs have worked. Whether it’s because of the delivery method, the drug’s efficacy or the physiology of the specific pain response isn’t clear.
The team recruited 370 female patients who had never given birth before to test whether the local anaesthetic Mepivacaine would provide a significant benefit over no pain relief.
Trial Design
The women were recruited from a pool of patients who had opted to have an IUD fitted aged between 18 and 31 years. The researchers gathered information about each volunteer and asked an uninvolved member of staff to randomize them into two matched groups. One group of 185 would get Mepivacaine during their procedure; the other 185 would get saline solution.
None of the women, nor the health professionals inserting IUD would know whether they were in the control group or the experimental group. The research coordinators took a third precaution to ensure a lack of bias in interpreting the results by not revealing which patients were in which group until after the analysis was complete.
Experienced midwives or gynaecologists threaded a 1.6-mm sterile hydrosonography catheter through each woman’s cervical opening and 1–2 cm into the uterus. Then they squirted a solution of either 10 ml saline (the placebo control) or 10 ml of 20 mg/ml Mepivacaine through the tube into the uterus. The idea was to numb the inside of the uterus and the cervix. After two minutes they used their usual method to insert an IUD, either a copper IUD (Nova-T 380, 3.6 mm) and the 19.5-mg or 13.5-mg levonorgestrel-releasing hormonal IUD (3.8 mm). The study arms were not outside the tube.
Testing “Tolerability” of IUD Placement
Participants used the visual analogue score pain scale to describe how painful the procedure was compared to the worst menstrual pain they had ever experienced. Volunteers gave a baseline reading before the procedure, marked on the chart the intensity of pain just after the anaesthetic, during the IUD insertion and then ten minutes after speculum removal. At each point, the researchers checked in with the patients asking if the pain was tolerable.
After they removed the speculum, the researchers asked the volunteers some additional questions: was their experience easier than expected, as expected, or worse than expected? Whether they would like additional oral analgesia? Would they recommend the pain relief method to a friend? Would they still have chosen an IUD had they known in advance how the procedure would feel?
The researchers used simple statistical tests to see how different the answers given by women who got the local anaesthetic gave to the women who got a placebo.
Does Local Anesthetic Provide Meaningful Pain Relief During IUD Insertion?
Of the 370 IUD insertions, quite a few didn’t make it into the final analysis. In twelve cases the midwife or doctor couldn’t insert the IUD. In 56 cases they couldn’t pass the catheter through the cervix to deliver the treatment (saline or anaesthetic).
At the final data collection, 170 of the Mepivacaine group and 167 of the control group completed the final follow up three months later. So did Mepivacaine help? Simply put, yes. Before the IUD insertion, the women rated their pain at an average of 1.8 units. During insertion of the IUD, women who got the saline solution said their pain was an average of 58.6 units, while women who got the numbing treatment rated their pain 14 points lower at 43.8 units. Notably women who got the anaesthetic were 50% less likely to experience severe pain (70 or more units).
Women who got the anaesthetic rated their pain lower than women who got the placebo at all points of the procedure and were 50% more likely than women who got the placebo to say it was easier than expected. A third of the women who got the saline solution said the whole thing was worse than expected vs 15% of women who got pain relief.
What Should “Tolerable” Mean?
Overall it seems like women who tried Mepivacaine had a better experience than women who didn’t. A few things to note are that the trial design begged the questions. While 91% of women who got saline solution said the pain was ‘tolerable’, should ‘tolerable’ be what we are aiming for? Is the worst menstrual pain a person has ever experienced a good read out of an acceptable level of pain? Are yes or no questions that could be interpreted as critical of the person doing the procedure while the patient is in an extremely vulnerable position going to elicit genuine responses?
On the other hand, there was a clear difference in pain ratings between the two groups, indicating that this local anaesthetic is better than a placebo.
Fingers crossed, gynaecologists will continue to pursue pain relief for routine procedures.
Source
Elgemark K, Envall N, Kopp Kallner H. Intrauterine Mepivacaine Instillation vs Placebo for Pain During IUD Placement: A Randomized Clinical Trial. JAMA. 2026;336(16):1436-1443. doi:10.1001/jama.2026.14217
