A Cochrane review included 10 studies; 6 studies compared different oral contraceptive pill (OCP) preparations with placebo and 4 compared different preparations with each other. No studies compared OCP with non steroidal anti-inflammatory drugs.
OCPs were better in pain relief than placebo (Peto OR 2.01, 95% CI 1.32 to 3.08; 7 studies, n=497; significant heterogeneity I2 = 64%). After removing the studies with inadequate allocation concealment, the OR was 2.99 (95% CI 1.76 to 5.07; 4 studies, n=370) with no heterogeneity. There was no difference in pain relief between different 3rd generation progestagens (gestodene vs desogestrel) (OR 1.11, 95% CI 0.79 to 1.57; 2 studies, n=626). One study suggested better pain relief with 3rd generation (desogestrel) compared to 2nd generation (levonorgestrel) OCP (OR 0.44, 95% CI 0.23 to 0.84; 1 study, n=349). Only 3 studies reported adverse effects, which included nausea, headaches and weight gain. There was no statistically significant difference between OCPs and placebo in the outcome of experiencing any side effect (OR 1.45, 95% 0.71 to 2.94; 2 studies, n=165).
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment) and by indirectness (the majority of oral contraceptive pills prescribed today include much lower levels of oestrogen and progestogen and often different types of progestogens than some of the trials included in this review).