Comment: The quality of evidence is downgraded by study limitations (unclear allocation concealment and unclear blinding in half othe studies, and selective reporting), by imprecise results (few patients and events for one comparison), and by inconsistency (unexplained variability in results).
A Cochrane review [Abstract] 1 included 50 studies with a total of 6 510 subjects. Oral antioxidants, including combinations of antioxidants, pentoxifylline, N-acetyl-cysteine, melatonin, L-arginine, vitamin E, myo-inositol, vitamin C, vitamin D+calcium and omega-3-polyunsaturated fatty acids were compared with placebo, with no treatment/standard treatment or another antioxidant. Antioxidants were associated with an increased live birth rate and clinical pregnancy rate compared with placebo or no treatment/standard treatment T1. This suggests that among subfertile women with an expected live birth rate of 20%, the rate among women taking antioxidants would be between 26% and 43%. Pentoxifylline was associated with an increased clinical pregnancy rate compared with placebo or no treatment (OR 2.03, 95% CI 1.19 to 3.44, P = 0.009; 3 RCTs, n=276, I²= 0%) but in one study there was no difference in live birth (OR 1.54, 95% CI 0.68 to 3.50, n=112).
| Outcome | Relative effect(95% CI) | Risk with control - Placebo or no treatment/standard treatment | Risk with intervention - Antioxidant(s) (95% CI) | №of participants(studies) Quality of evidence |
|---|---|---|---|---|
| Live birth | OR 2.13(1.45 to 3.12) | 196 per 1000 | 342 per 1000(262 to 433) | 651(8) Very low |
| Clinical pregnancy | OR 1.52(1.31 to 1.76) | 220 per 1000 | 301 per 1000(270 to 332) | 4271(26) Very low |
| Adverse events - Miscarriage | OR 0.79(0.58 to 1.08) | 68 per 1000 | 55 per 1000(41 to 73) | 2834(18) Very low |
| Adverse events - Multiple pregnancy | OR 1.00(0.73 to 1.38) | 80 per 1000 | 80 per 1000(60 to 107) | 2163(8) Very low |
| Adverse events - Gastrointestinal disturbances | OR 1.55(0.47 to 5.10) | 24 per 1000 | 37per 1000(12 to 112) | 343(3) Very low |
Date of latest search: 2018-01-22
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