Combined Oral Contraceptives Ease Menstrual Pain

Troy Brown

January 20, 2012

January 20, 2012 — A recent study found that combined oral contraceptives (COCs) and, to a lesser extent, increasing age reduced the severity of dysmenorrhea in women aged 19 to 24 years.

Ingela Lindh, PhD, and colleagues Agneta Andersson Ellström, MD, PhD, and Ian Milsom, MD, PhD, all from the Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University, Sweden, reported their findings in an article published online January 17 in Human Reproduction.

They used 2 tools, a verbal multidimensional scoring system (VMS) and a visual analogue scale (VAS), to evaluate dysmenorrhea in 3 groups of women at 19 and 24 years of age.

The researchers used the population registers from the city of Gothenburg to identify women who were 19 years old in 1981, 1991, and 2001. They picked every fourth woman from the register in 1981, and every third woman from the registers in 1991 and 2001.

The women all resided in Gothenburg at the time of birth and at the times of assessment. They were born in 1962 (62 cohort), 1972 (72 cohort), and 1982 (82 cohort) and were first evaluated at age 19 years in 1981 (n = 489), 1991 (n = 523), and 2001 (n = 392), respectively. They were evaluated again 5 years later, at age 24 years.

The team sent postal questionnaires with about 40 questions regarding contraception, reproductive history, menstrual pattern, duration and intensity of menstrual pain, need for medical care, ability to work during menses, and information including height, weight, and smoking status.

The VMS instructs the individual to rate their pain as none, mild, moderate, or severe. The VAS has the person rate their pain along a straight line representing a continuum of 1 to 10, with "no pain at all" at one end and "unbearable" pain at the other.

The researchers performed a correlation analysis to compare the VMS and VAS in all women who completed them at both ages. They found a significant correlation (r = 0.83; P< .0001) between reports of dysmenorrhea by both tools; therefore, they report the VMS results as mean values.

The researchers compared menstrual bleeding pattern and dysmenorrhea severity both within and between the 3 cohorts at 19 and 24 years of age. Fewer women in the 82 cohort reported no dysmenorrhea on the VMS than in the other 2 cohorts.

Participants in the 82 cohort had a higher VMS score at 19 and 24 years of age (P < .05 and P < .001) compared with the 62 cohort, and a higher VMS score at age 24 than the 72 cohort (P < .01).

The 82 cohort reported more severe dysmenorrhea on the VAS compared with the 62 cohort (P < .001) and the 72 cohort (P < .01) at ages 19 and 24 years, respectively.

Dysmenorrhea-related absenteeism was 31% to 33% at 19 years of age and decreased in all 3 groups at age 24 years to 20% to 23%.

The researchers placed the women in 1 of 2 groups: those who used COCs at age 19 years, but not at age 24 years, and those who did not use COCs at age 19 years, but did at age 24 years, and compared these groups with each other. Women were excluded from these analyses if they had given birth, used an intrauterine device, or used progestogen-only contraception methods.

When all 3 cohorts were analyzed together, women who used COCs at age 19 years, but not at age 24 years, had increased severity of dysmenorrhea, and women who did not use COCs at age 19 years, but did at age 24 years, had decreased dysmenorrhea severity.

The decrease in dysmenorrhea between the cohorts was demonstrated equally by the VMS tool (0.58, confidence interval, 0.35 - 0.81; P < .0001) and the VAS tool (18.8, confidence interval, 11.6 - 26.0; P < .0001).

One study limitation is that few women included in the trial gave birth, which reduced the ability to assess the effect of childbirth on dysmenorrhea.

"The study was a large longitudinal cohort study that used patients as their own controls, as it was done over time. The age-related findings may have had a decrease in smoking and increase in weight as confounders, but showed a statistically significant decrease in dysmenorrhea with the use of COCs," Leah Kaufman, MD, residency program director, North Shore Long Island Jewish/Hofstra School of Medicine, New York City, told Medscape Medical News in an interview.

"When analysing the cohorts separately, a corresponding decreased severity of dysmenorrhoea was noted for the 62 and 72 cohorts according to both measurement systems, but in the 82 cohort only when using the VAS," write the Dr. Lindh and colleagues.

COCs and increasing age reduced severity of dysmenorrhea independent of each other, according to the authors, and COCs reduced dysmenorrhea more than increasing age or childbirth. "The decrease in the severity of dysmenorrhoea achieved by COCs was equivalent to the transfer of every third woman one step down on the VMS scale, which — in clinical terms — will result in less pain, improved working ability and a decrease in the need for analgesics," the authors write.

"Effective management of dysmenorrhoea is beneficial for both the afflicted individual and society and thus the possibility of a beneficial influence of COCs on dysmenorrhea should be included in contraceptive counselling," write the authors.

Dr. Kaufman agrees. "As a practicing generalist [obstetrician/gynecologist,] I regularly prescribe COC's for the treatment of dysmenorrhea, with marked improvement in their functionality and a decrease in their absenteeism from work and school," she said.

"The potential issue of difference in pain perception and a decrease in pain, particularly with respect to dysmenorrhea associated with age, was suggested in the article, but not proven. Differential pain perception by age and the need for physicians to tailor treatment and counseling based on this concept would be interesting, if proven with the elimination of other confounding factors," she explained.

"[I]t is desirable that the findings from this study providing evidence for a beneficial effect of COCs in dysmenorrhea be confirmed by a placebo-controlled, randomized trial where the efficacy of COCs in dysmenorrhea are assessed as a primary outcome measure," the authors conclude.

The study was supported by grants from the Gothenburg Medical Society, Hjalmar Svenssons Fund, and a National LUA/ALF grant. Dr. Lindh and Dr. Milsom have, during the last 5 years, participated in clinical trials sponsored by Organon. Dr. Milsom also has participated in International Advisory Boards sponsored by Organon/Schering-Plough/MSD and Schering/Bayer Pharma and has received lecture fees for presentations sponsored by Organon, Schering/Bayer, and Pfizer. Dr. Lindh has received lecture fees from Organon/MSD. Dr. Ellström and Dr. Kaufman have disclosed no relevant financial relationships.

Hum Reprod. Published online January 17, 2012. Abstract


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