Combined oral contraceptive for dysmenorrhoea
Clinical bottom line
The evidence is not overwhelming, but there may be an additional benefit of pain relief for one women in five taking oral contraceptive pills. This may be sufficient to consider OCP for dysmenorrhoea when contraception is also required.
Background
Use of oral contraceptives for treating dysmenorrhoea has been advocated since the 1960s, though experimental backing has been lacking.
Reference
ML Proctor et al. Combined oral contraceptive pill (OCP) as treatment for primary dysmenorrhoea. Cochrane Database of Systematic Reviews 2001 issue 2.
Systematic review
A wide search was conducted for randomised trials comparing any type of combined oral contraceptive containing oestrogen and progestagen with other contraceptives, placebo, or no treatment.
Results
Five randomised trials were found, all dating from the late 1960s or early 1970s. None was particularly large, and for the four that had combinable data there were only 320 women. Trials used different types or doses of oestrogen or progestagen.
The problems with the evidence can be seen in Figure 1, which shows the proportion of women having pain relief with OCP or placebo for four trials. Results are not consistent.
Figure 1: Pain relief with OCP or placebo
When the information is combined, whether it is statistically significant overall depends on what attitude one takes. One statistical model says there is a significant difference, while another says there is no difference.
However, overall 52% of women benefited with OCP, compared with 31% with placebo. This gives a number needed to treat of 5 (95% confidence interval 3 to 10). This may be sufficient to consider OCP for dysmenorrhoea when contraception is also required.
Comment
The evidence is not overwhelming, but there may be an additional benefit of pain relief for one women in five taking oral contraceptive pills.