How to reduce the potential harmful effects of light on blastocyst development during IVF.

PURPOSE Earlier findings revealed the damaging effect of visible light on zygotes and gametes. The aim of our study is to eliminate or significantly reduce the potential harmful effect of light exposure during in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) and to investigate the effect of light protection on embryo development and implantation. MATERIALS/METHODS To protect sperm cells, oocytes and embryos from the potential harmful effects of light exposure during laboratory procedures, we created a dark environment for the cells and applied red filters on laboratory lamps and UV or infrared filters in the microscopes - to eliminate white light exposure of the cells throughout all work stages. RESULTS The fertilization rate was significantly (p = 0.011) higher in light protected ICSI cycles. Blastocyst development rates (blastocyst/embryo) were significantly (p<0.001) higher in light protected embryos than in those manipulated in conventional light conditions both in IVF (20.9% difference) and ICSI (38.6% difference). Number of clinical pregnancies/transfers of ICSI fertilized day 5 blastocysts were significantly (p=0.040) higher in light protected conditions. CONCLUSIONS This data show that light protection has a positive effect on fertilization rate and increases the blastocyst development as well as number of clinical pregnancies/transfers. Implementation of this light protection method in IVF centers may improve the success rate while maintaining maximal embryo safety.