Poor egg (oocyte) quality is an important cause of female infertility. Low quality eggs may have several problems, for example they may not divide properly, or they may be missing certain chromosomes. Egg quality also declines with age, and certain medical conditions, such as PolyCystic Ovary Syndrome, can lead to poor quality eggs.

New research presented at the World Congress of Fertility and Sterility in Munich has found that treating women with the hormone melatonin may help improve the egg quality in IVF.

A group led by Associate Professor Hiroshi Tamura (Yamaguchi University Graduate School of Medicine, Japan) measured the presence of the oxidizing agent 8-OHdG in follicular fluids. High levels of oxidising agents such as 8-OHdG is an indicator of poor egg quality. The group found that as melatonin concentration in the folliclar fluids naturally increased, the level of 8-OHdG went down, leading the group to believe that melatonin was linked to the reduction of the stressing oxidising agents. Melatonin has known anti-oxidizing effects.

They confirmed this finding in mice, and noted that addition of melatonin seemed to reduce the damage to the egg caused by the presence of oxidising agents.

The group then initiated a trial with a group of women coming for IVF treatment at the Yamaguchi University Graduate School of Medicine. Women who had failed to become pregnant because of poor oocytes quality after one cycle of IVF were split into two groups; 56 women were given 3 mg of melatonin before the next IVF cycle, and 59 just received a standard IVF cycle without any melatonin.

The team found that melatonin treatment significantly increased intrafollicular melatonin concentrations, and significantly decreased the concentration of the damaging 8-OhdG.

The results of the study found that 50% of the eggs from women who taken melatonin could be successfully fertilised, as opposed to 22.8% in the control group. When the eggs were then transplanted into the womb, 19% (11 out of the total 56) of the women became pregnant, as opposed to 10.2% (6 out of total 59) in the control group.

Associate Professor Tamura commented

"Despite great advances in assisted reproductive technology, poor oocyte quality remains a serious problem for female infertility, and so far no practical and effective treatment for improving oocyte quality has been established. Our work show that oxidizing agents can lessen oocyte quality, and that this can be countered by action of the hormone melatonin. In addition, our clinical trial shows that melatonin treatment improves oocyte quality, leading to a higher fertilization rate.

To our knowledge, our study represents the first clinical application of melatonin treatment for infertility patients. 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.

Our next step is to analyze exactly how reactive oxygen species harm the oocyte, and how melatonin reduces oxidative stress in the oocyte".

Sources: International Federation of Fertility Societies, AlphaGalileo Foundation.