Copper IUDs Not Associated With Increased Menstrual Pain

Jenni Laidman

May 10, 2013

Copper intrauterine contraceptive devices (Cu-IUDs) did not increase pain during menstruation, and a levonorgestrel-releasing intrauterine system (LNG-IUS) reduced dysmenorrhea, according to results from a long-term study of 2102 women published online April 11 in Human Reproduction.

Ingela Lindh, PGDipMidw, and Ian Milsom, both from the Department of Obstetrics and Gynecology, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University, Sweden, recruited 3 groups of 19-year-old women (656 born in 1962, 780 born in 1972, and 666 born in 1982) and surveyed them every 5 years between 1981 and 2001. The mailed questionnaire enquired about height, weight, smoking, contraception, reproductive history, menstruation pattern, duration and severity of pain, need for medical attention, and ability to work during menstruation. The authors compared the prevalence and severity of menstrual pain for women using Cu-IUDs, a LNG-IUS, combined oral contraceptives (COCs), other contraception methods, and no contraception.

The questionnaire used a verbal multidimensional scoring system (VMS) in which women reported pain as none, mild, moderate, or severe on a scale of 0 to 3. The survey also employed a visual analog scale (VAS) in which respondents selected a point along a 100-mm line in which one end of the line stood for no pain and the other end for unbearable pain.

The investigators found no increase in dysmenorrhea severity among women using CU-IUDs compared with women when using no contraception or other nonhormonal contraceptive methods, such as condoms (VMS score, +.05 units; VAS, −0.3 mm; both nonsignificant.) The study also confirmed earlier research showing that dysmenorrhea severity lessened when women used an LNG-IUS and COCs compared with other methods of contraception or no contraception. (LNG-IUS use: VMS score, −0.4 units; VAS, −13 mm [both P < .01]; COC use: VMS score, −0.4 units; VAS, −11 mm [both P < .0001]).

LNG-IUS has been previously associated with a reduction in dysmenorrhea severity, but Cu-IUDs have a reputation for enhancing menstruation pain.

The study is a step toward broader acceptance of IUDs, particularly among women in the United States, where the devices remain unpopular, Andrew M. Kaunitz, MD, professor and associate chairman, Department of Obstetrics and Gynecology, University of Florida College of Medicine, Jacksonville, told Medscape Medical News. Dr. Kaunitz was not involved in the study.

"I see IUDs as very much underutilized," Dr. Kaunitz said. This study is important because it potentially removes a barrier to their use. "I'm not aware of any previous large, high-quality studies that look at copper IUDs and dysmenorrhea, so it's very useful information refuting concerns about pain."

Less than 5.5% of US women using contraception employ IUDs compared with 20% to 30% of all women in Finland, Norway, and Sweden reporting IUD use, the authors state.

Study weaknesses include a declining rate of participation during the 20 years of the survey and the fact that the questionnaire sought no information on endometriosis or adenomyosis. Among the study's strengths is the authors' decision to clearly distinguish between menstrual pain and pain between periods.

Lindh has received lecture fees from Organon/Schering-Plough/MSD and Bayer Pharma, as well as lecture fees from Organon, Schering/Bayer, and Pfizer. Milsom has participated in International Advisory Boards sponsored by Organon/Schering-Plough/Merck Sharp & Dohme and Schering/Bayer Pharma. Dr. Kaunitz has worked as a consultant for IUD makers Teva and Bayer, and the University of Florida has received research grants from the companies.

Hum Reprod. Published online April 11, 2013. Abstract