Antioxidants for male subfertility

[Intervention Review]
Antioxidants for male subfertility

Marian G Showell1, Julie Brown1, Anusch Yazdani2, Marcin T Stankiewicz3, Roger J Hart4

1Obstetrics and Gynaecology, University of Auckland, Auckland, New Zealand. 2Clinical Research and Development, Queensland Fertility Group, Woolloongabba, Australia. 3Reproductive Medicine, Flinders Reproductive Medicine, Bedford Park, Australia. 4School of Women's and Infants Health, The University of Western Australia, King Edward Memorial Hospital and Fertility Specialists of Western Australia, Subiaco, Australia

Contact address: Marian G Showell, Obstetrics and Gynaecology, University of Auckland, Park Road Grafton, Auckland, New Zealand. m.showell@auckland.ac.nz.

Editorial group: Cochrane Menstrual Disorders and Subfertility Group.
Publication status and date: New, published in Issue 1, 2011.
Review content assessed as up-to-date: 21 August 2010.

Citation: Showell MG, Brown J, Yazdani A, Stankiewicz MT, Hart RJ. Antioxidants for male subfertility. Cochrane Database of Systematic Reviews 2011, Issue 1. Art. No.: CD007411. DOI: 10.1002/14651858.CD007411.pub2.

Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
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Abstract

Background
Between 30% to 80% of male subfertility cases are considered to be due to the damaging effects of oxidative stress on sperm. Oral supplementation with antioxidants may improve sperm quality by reducing oxidative stress.

Objectives
This Cochrane review aimed to evaluate the effect of oral supplementation with antioxidants for male partners of couples undergoing assisted reproduction techniques (ART).

Search strategy
We searched the Cochrane Menstrual Disorders and Subfertility Group Register, CENTRAL (The Cochrane Library), MEDLINE, EMBASE, CINAHL, PsycINFO and AMED databases (from their inception until Febuary 2010), trial registers, sources of unpublished literature, reference lists and we asked experts in the field.

Selection criteria
We included randomised controlled trials comparing any type or dose of antioxidant supplement (single or combined) taken by the male partner of a couple seeking fertility assistance with placebo, no treatment or another antioxidant. The outcomes were live birth, pregnancy, miscarriage, stillbirth, sperm DNA damage, sperm motility, sperm concentration and adverse effects.

Data collection and analysis
Two review authors independently assessed studies for inclusion and trial quality, and extracted data.

Main results
We included 34 trials with 2876 couples in total.

Live birth: three trials reported live birth. Men taking oral antioxidants had an associated statistically significant increase in live birth rate (pooled odds ratio (OR) 4.85, 95% CI 1.92 to 12.24; P = 0.0008, I2 = 0%) when compared with the men taking the control. This result was based on 20 live births from a total of 214 couples in only three studies.

Pregnancy rate: there were 96 pregnancies in 15 trials including 964 couples. Antioxidant use was associated with a statistically significant increased pregnancy rate compared to control (pooled OR 4.18, 95% CI 2.65 to 6.59; P < 0.00001, I2 = 0%).

Side effects: no studies reported evidence of harmful side effects of the antioxidant therapy used.

Authors' conclusions
The evidence suggests that antioxidant supplementation in subfertile males may improve the outcomes of live birth and pregnancy rate for subfertile couples undergoing ART cycles. Further head to head comparisons are necessary to identify the superiority of one antioxidant over another.

Plain language summary

Antioxidants for male subfertility
Oxidative stress may cause sperm cell damage. This damage can be reduced by the body's own natural antioxidant defences. Antioxidants can be part of our diet and taken as a supplement. It is believed that in many cases of unexplained subfertility, and also in instances where there may be a sperm-related problem, taking an oral antioxidant supplement may increase a couple's chance of conceiving when undergoing fertility treatment. This review identified 34 randomised controlled trials involving 2876 couples. Pooled findings support increases in live births and pregnancy rates with the use of antioxidants by the male partner. Further work is recommended to confirm these findings.