Review question: Do supplementary oral antioxidants compared with placebo, no treatment/standard treatment or another antioxidant improve fertility outcomes for subfertile women (standard treatment includes folic acid < 1 mg).
Background: many subfertile women undergoing fertility treatment also take dietary supplements in the hope of improving their fertility. This can be a very stressful time for women and their partners. It is important that these couples be given high quality evidence that will allow them to make informed decisions on whether taking a supplemental antioxidant when undergoing fertility treatment will improve their chances or cause any adverse effects; this is especially important as most antioxidant supplements are uncontrolled by regulation. This review aimed to assess whether supplements with oral antioxidants increase a subfertile woman's chances of becoming pregnant and having a baby.
Search date: The evidence is current to April 2013.
Study characteristics: The review included 28 randomised controlled trials that compared antioxidants with placebo or no treatment/standard treatment, or with another antioxidant in a total of 3548 women.
Funding sources: Funding sources were reported by only six of the 28 included trials.
Key results: Antioxidants were not found to be effective for increasing rates of live birth or clinical pregnancy. Based on these results, we would expect that out of 100 subfertile women not taking antioxidants, 23 would become pregnant, compared with between 22 and 36 per 100 who would become pregnant if taking antioxidants to improve their chances of becoming pregnant. Antioxidants did not appear to be associated with the adverse events of miscarriage or multiple or ectopic pregnancy.