Abstract
Study question
Do different wavelengths and intensities in ambient lighting affect clinical outcomes?
Summary answer
Variations on ambient lighting intensity and wavelength do not affect life birth rates.
What is known already
Light is one of the factors to consider when designing an IVF laboratory. Most IVF clinics work under reduced illumination, trying to mimic uterine conditions as much as possible. Nevertheless, it has been described that 95% of the light that affects an embryo comes from the microscope, not ambient lighting.
It is well accepted that exposure to extreme lighting conditions affects embryos through photo-oxidation and the creation of reactive oxygen species. Still, there is no study that documents the effect of different wavelengths on human embryos.
Study design, size, duration
Prospective study performed between january 2019 and february 2020. Every 60 days we changed ambient illumination conditions using the LED lighting installed throughout the IVF laboratory. Six different groups were created: Cyan (470nm), Green (550nm), Yellow (600nm), Orange (625nm), intense white (WH), and low intensity white (WL) as control group.
Participants/materials, setting, methods
A total of 572 egg donation cicles with 355 fresh single embryo transfers were included in the study. In all cycles ICSI and Time-lapse culture was performed (Embryoscope, Vitrolife). PGT and testicular biopsy/aspiration treatments were excluded. Eggs and embryos were exposed to ambient illumination during pick-up, denudation, ICSI, and embryo transfer procedures.
Main results and the role of chance
Light exposure during embryo/gamete manipulation is inevitable. Hence, we analyzed parameters linked to the success of an IVF cycle to assess the effect of different lighting conditions concluding that neither light color nor intensity affect IVF success rates.
No differences were found between groups regarding maternal age, age of the recipient, diagnostic, or number of eggs received (p > 0.05). Fertilization rates were similar between groups (C = 77.04%; G = 73.72%; Y = 75.64%; O = 78.1%; WL = 76.4%; WH = 75.2%; p = 0.216) as well as good quality blastocyst rates (C = 57.35%; G = 57.37%; Y = 62.30%; O = 59.75%; WL = 63.28%; WH = 60.55%; p = 0.234). Regarding clinical outcomes both implantation and miscarriage rates were found to be equal between groups (C = 61.67%; G = 52.89%; Y = 55.10%; O = 66.18%; WL = 66.00%; WH = 53.55%; p = 0.194, and C = 24.32%; G = 19.15%; Y = 11.11%; O = 24.44%; WL = 15.15%; WH = 8.11%; p = 0.301). The main outcome for this study was live birth rates and no differences were found (C = 51.85%; G = 50.00%; Y = 52.17%; O = 53.97%; WL = 57.14%; WH = 50.75%; p = 0.168).
Limitations, reasons for caution
We must take into account that embryos were cultured inside a time-lapse incubator, diminishing the effect of ambient light.
Wider implications of the findings: This study demonstrates that, with advances in culture technology, neither light intensity nor light wavelength affecting gametes/embryos during manipulation influence clinical outcomes.
Trial registration number
Not applicable
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