# Reducing Photo-Oxidative Stress in IVF: A Retrospective Analysis of Cycles with Poor Blastocyst Development

## TL;DR

This study found that reducing light exposure in IVF labs may help improve pregnancy outcomes for embryos with poor development.

## Contribution

The study introduces a light-protection protocol in IVF labs and evaluates its impact on pregnancy outcomes.

## Key findings

- Overall pregnancy rates increased by about 5% after implementing light protection, though not statistically significant.
- Pregnancy outcomes improved by up to 37% in cycles with low blastocyst-formation rates.
- Light protection may benefit embryos with reduced developmental competence by minimizing photo-oxidative stress.

## Abstract

Background: The success of in vitro fertilization (IVF) is influenced by multiple patient- and laboratory-related factors, including maternal age, body mass index (BMI), ovarian stimulation, and embryo quality. Laboratory illumination may induce photo-oxidative stress, potentially impairing embryo development and implantation. This study evaluated the clinical impact of introducing a light-protection protocol in an IVF laboratory. Methods: We retrospectively analyzed 2125 IVF cycles with fresh embryo transfer performed at the Assisted Reproduction Centre of the University of Pécs between 1 March 2016 and 30 November 2020. A light-protection protocol was implemented on 1 March 2017, while all other laboratory and clinical parameters remained unchanged. Pregnancy outcomes before and after implementation were compared, with additional subgroup analyses focusing on cycles with low blastocyst-formation rates. Results: After implementation of light protection, overall pregnancy rates increased by approximately 5%; however, this difference was not statistically significant. In contrast, subgroup analyses demonstrated a markedly greater improvement in pregnancy outcomes—up to 37%—in cycles characterized by low blastocyst-formation rates. Conclusions: Although light protection did not significantly improve overall pregnancy rates, the findings suggest a clinically relevant benefit in selected cases with reduced embryonic developmental competence. Minimizing photo-oxidative stress may therefore represent a targeted laboratory intervention to improve IVF outcomes in vulnerable embryo populations.