Combined Oral Contraceptives for Primary Dysmenorrhea

Are combined oral contraceptives safe and effective for the management of primary dysmenorrhea?

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

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).