1.4. Analysis.

Comparison 1 NSAIDs versus placebo, Outcome 4 MBL and other outcomes (descriptive results).

MBL and other outcomes (descriptive results)
Study
Mefenamic acid vs placebo
Fraser 1981	Mean menstrual blood loss (standard deviation (SD)) on placebo: 70.7 (24.9) mL Mean menstrual blood loss (SD) on mefenamic acid: 47.3 (21.7) mL P < 0.001, n = 28, paired t test, t = 6.56 Other outcomes were not given for this subgroup.
Muggeridge 1983	Mean menstrual blood loss (SD) on placebo: 161 (78.5) mL Mean menstrual blood loss (SD) on mefenamic acid: 128.3 (78.1) mL No significant difference between placebo and mefenamic acid (MFA) cycles, n = 15, Wilcoxon Sum Rank Test Mean score of dysmenorrhoea symptoms (SD) in 2nd placebo cycle: 2.1 (2.1) Mean score of dysmenorrhoea symptoms (SD) in 2nd MFA cycle: 1.3 (1.6) No significant difference between placebo and MFA cycles, n = 15, Wilcoxon Sum Rank Test
Tsang 1987	Mean menstrual blood loss (SD) on placebo: 156.5 (105.9) Mean menstrual blood loss (SD) on MFA: 140.0 (109) P < 0.05, n = 10, t test comparing MFA cycles with combined placebo and control cycles
Naproxen vs placebo
Rybo 1981	Mean menstrual blood loss (standard deviation (SD)) on placebo: 144 (26) mL Mean menstrual blood loss (SD) on naproxen: 107 (154) mL P < 0.02, n = 4, statistical method not given
Ylikorkala 1986	Mean menstrual blood loss (SD) on placebo: 150.7 (34) mL Mean menstrual blood loss (SD) on naproxen: 96.8 (27.3) mL P < 0.001, n = 14, paired t test Proportion of women with adverse effects on placebo: 7% Proportion of women with adverse effects on naproxen: 0% Not tested
Ibuprofen vs placebo
Makarainen 1986	Median menstrual blood loss (range) on placebo: 146 (71–374) mL Median menstrual blood loss (range) on ibuprofen 600 mg: 123 (23–319) mL Median menstrual blood loss (range) on ibuprofen 1200 mg: 110 (30–288) mL P < 0.01, n = 13, Wilcoxon paired test, ibuprofen 1200 vs placebo