Thursday, 2 September, 2010

Hormone melatonin improves egg quality in IVF

Women with poor egg (or oocyte) quality could double their chance of becoming pregnant through IVF if given melatonin, researchers have found.

'Despite great advances in assisted reproductive technology, poor oocyte quality remains a serious problem for female infertility', said Professor Hiroshi Tamura from the Yamaguchi University Graduate School of Medicine, Japan, who led the research. 'So far no practical and effective treatment for improving oocyte quality has been established'.

High levels of oxidising agents - a type of chemical compound - in the follicular fluids surrounding the egg indicate if a woman has low quality oocytes. These can 'stress' and damage the oocyte. The team took one of these agents known as8-OHdG and measured its levels in follicular fluid samples. Levels of melatonin, which is known to have anti-oxidising effects, were also measured.

The team found that, as melatonin concentration in the follicular fluids naturally increased, the level of 8-OHdG decreased, leading them to believe melatonin was linked to the reduction of the oxidising agents. They confirmed this finding in mice, and discovered that adding melatonin seemed to reduce the damage to the egg caused by the agents.

Next, the group set up a trial with women coming for IVF treatment at the Yamaguchi University Graduate School of Medicine to see if these findings could have real-world effects on IVF. Women who had failed to become pregnant because of poor oocyte quality after one cycle of IVF were split into two groups - 56 women were given three milligrams of melatonin before the next IVF cycle, and 59 just received a standard IVF cycle without melatonin.

The team found that melatonin treatment significantly increased melatonin concentrations in the women's follicles and significantly decreased concentrations of the damaging 8-OhdG. Their results showed 50 per cent of the eggs from women who taken melatonin could be successfully fertilised, as opposed to 22.8 per cent in the control group. When the eggs were transplanted into the womb, 19 per cent (11 out of the total 56) of the women became pregnant, as opposed to 10.2 per cent (six out of total 59) in the control group. The work was published in the Journal of Pineal Research.

'This work needs to be confirmed, but we believe that melatonin treatment is likely to become a significant option for improving oocyte quality in women who cannot become pregnant because of poor oocyte quality', said Professor Tamura. 'Our next step is to analyze exactly how reactive oxygen species harm the oocyte, and how melatonin reduces oxidative stress in the oocyte'.

Professor Russel Reiter from the UT Health Science Center, San Antonio, Texas, who co-authored the paper, agreed. 'it is important that this work be independently confirmed on larger numbers of subjects'. But he added that the findings 'make perfect sense', as melatonin has been shown to protect many different cells and tissues from oxidative damage - the same type of damage known to occur to oocytes.

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