Clinical Question
Are combined oral contraceptives safe and effective for the management of primary dysmenorrhea?
Evidence-Based Answer
Combined oral contraceptives reduce pain associated with primary dysmenorrhea compared with placebo (standardized mean difference [SMD] = −0.58; 95% CI, −0.74 to −0.41). (Strength of Recommendation [SOR]: A, based on consistent, good-quality patient-oriented evidence.) Oral contraceptives increase the risk of any adverse effects when compared with placebo (number needed to harm [NNH] = 5; 95% CI, 4 to 8; SOR: A, based on consistent, good-quality patient-oriented evidence), although the risk of serious adverse events is unclear due to few events.1
Practice Pointers
Dysmenorrhea is recurrent cramping and lower abdominal pain associated with menses. Up to 50% to 90% of reproductive-aged women meet the criteria for dysmenorrhea in their lifetime, and approximately one-half miss work or school at least once due to symptoms.2 Primary dysmenorrhea occurs in the absence of underlying pathology. The authors of this Cochrane review sought to determine the benefits and harms of combined oral contraceptives in the treatment of primary dysmenorrhea.
The Cochrane review included 21 randomized controlled trials (RCTs) with 3,723 women of reproductive age who had primary dysmenorrhea. In these trials, primary dysmenorrhea was diagnosed as moderate or severe pain—although it was not clear how moderate or severe was defined—for at least 1 day of menses, without obvious pelvic pathology on physical examination or ultrasonography.1 Among the RCTs reviewed, combined oral contraceptives were compared with placebo, nonsteroidal anti-inflammatory drugs (NSAIDs), and other oral contraceptives. The primary outcomes were improvement in self-reported pain and the incidence and type of adverse effects from treatment. Improvement in self-reported pain was assessed using a visual analog scale or other scale and the difference in the number of women experiencing pain relief. The authors counted only substantial changes in pain as pain relief because of subjectivity.
High-quality evidence from six RCTs using self-reported pain scales showed a moderate reduction in pain when using combined oral contraceptives compared with placebo or no treatment (SMD = −0.58; 95% CI, −0.74 to −0.41). Additional low-quality evidence from six trials using a dichotomous outcome (i.e., the number of women with pain scores that changed from one major pain score category to another) showed a reduction in pain with the use of oral contraceptives vs. placebo (risk ratio = 1.65; 95% CI, 1.29 to 2.10; number needed to treat [NNT] = 6; 95% CI, 3 to 12). Moderate-quality evidence showed little to no difference in benefit when eight formulations of oral contraceptives were compared. There may have been an additional benefit in pain relief when using a continuous oral contraceptive regimen vs. a cyclical regimen (i.e., 21 days of active tablets and 7 days of placebo; SMD = −0.73; 95% CI, −1.13 to −0.34); however, the evidence was low quality and included only two RCTs with 106 women. There was insufficient evidence to determine whether oral contraceptives were more effective than NSAIDs for pain relief from primary dysmenorrhea. For secondary outcomes, low-quality evidence suggested that compared with placebo or no treatment, oral contraceptives may have decreased the requirement for additional medication (NNT = 8; 95% CI, 5 to 125) and decreased absence from work or school (NNT = 8; 95% CI, 4 to 91).
Moderate-quality evidence showed that oral contraceptives may be associated with an increased risk of any adverse effect compared with placebo (risk ratio = 1.31; 95% CI, 1.20 to 1.43; NNH = 5; 95% CI, 4 to 8); however, there was significant heterogeneity in these studies (I2 = 79%). The most commonly reported adverse effects were irregular bleeding (NNH = 3; 95% CI, 2 to 4), headache (NNH = 11; 95% CI, 5 to 52), and nausea (NNH = 16; 95% CI, 8 to 62). Due to few reported events, it was unclear whether oral contraceptives increased the risk of serious adverse events. There was insufficient information to determine whether a continuous vs. standard regimen increased the risk of weight gain, absence from work or school, or withdrawal from activity due to adverse effects.
The American College of Obstetricians and Gynecologists recommends the use of oral contraceptives or NSAIDs for the treatment of primary dysmenorrhea.3 Family physicians should be prepared to discuss the risks and benefits of treatment options.
Patient Perspective
Almost every woman has experienced menstrual pain. For some, the pain is severe enough to affect daily functioning regularly. For others, the pain can be close to disabling, and in these situations, oral contraceptives can be a godsend. This may be especially true for teenagers who may or may not need contraception but who often have difficulties dealing with irregular or heavy periods. The caveat is that adverse effects of oral contraceptives are common, secondary causes of dysmenorrhea can be difficult to ascertain, and serious adverse events may be more frequent than is recognized. “The Pill” has changed women's lives, but patients should always be provided with the latest information about the differences among oral contraceptives, including over-the-counter pills, and how these might best fit their situation.
The practice recommendations in this activity are available at https://www.cochrane.org/CD002120.
The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the U.S. Navy, the U.S. Department of Defense, or the U.S. government.
