In assisted reproductive technology (ART), the in-vitro environment aims to replicate physiological (in-vivo) conditions as closely as possible. One of the most crucial factors influencing embryo development is the stability of culture conditions within incubators. Incubators are an essential tool as they provide a controlled environment for the development of embryos. Even minor fluctuations in temperature, pH, and gas concentrations in the incubator can induce stress on embryos and potentially alter developmental potential.
A commonly overlooked contributor to such fluctuations is the frequency of incubator door openings. Embryologists typically open incubator doors for routine tasks such as assessing embryo development, performing media changes, or transferring gametes and embryos. Each time the door is opened, incubators experience transient shifts in temperature and gas concentrations, followed by a recovery phase. Although modern incubators are designed with improved insulation and faster recovery times, repeated door openings may lead to cumulative stress on the embryos. In this blog, we will discuss the effects of incubator door opening on embryos and how to minimize its impact.
Scientific Evidence
Temperature and pH fluctuations: Lane & Gardner (2005) demonstrated that even short-term changes in culture temperature can alter embryo metabolism, leading to impaired developmental competence.
Gas stability: Studies have shown that frequent door openings affect CO₂ levels, resulting in pH fluctuations within the culture media, which can negatively influence embryo cleavage rates (Swain, 2014).
Clinical outcomes: Research indicates that laboratories with higher door-opening frequencies may experience subtle but significant reductions in blastocyst formation and embryo quality (Cohen et al., 1997; Morbeck, 2015).
Implications for IVF Laboratories
Workflow discipline: Reducing unnecessary door openings minimizes environmental stressors for embryos.
Shared incubators: In high-volume labs, frequent door access by multiple staff can compound disturbances, making monitoring particularly important.
Outcome optimization: Stable incubation conditions are directly correlated with improved fertilization, cleavage, and blastocyst development rates.
Moving Forward
To minimize the impact of door openings on embryos, it is crucial to minimize the frequency and duration of door openings. Incubator doors should only be opened when necessary, and for the shortest time possible. The incubator should also be located in an area with stable temperature and humidity levels, away from sources of heat or cold, and not subjected to frequent changes in ambient conditions
Another strategy to minimize the impact of incubator door opening is to use time-lapse imaging systems. These systems allow the embryos to be monitored without opening the incubator door. Time-lapse imaging systems can provide continuous monitoring of embryo development, allowing embryologists to select the best embryos for transfer without having to open the incubator door for each developmental check. By doing so, embryologists can better preserve the microenvironment critical for embryo development and, ultimately, improve clinical success rates.
References
Lane M, Gardner DK. (2005). Understanding cellular disruptions during early embryo development that perturb viability and fetal development. Reproduction Fertility and Development, 17(3): 371–378.
Swain JE. (2014). Decisions for the IVF laboratory: comparative analysis of embryo culture incubators. Reproductive BioMedicine Online, 28(5): 535–547.
Cohen J, Gilligan A, Esposito W, Schimmel T, Dale B. (1997). Ambient air and its potential effects on conception in vitro. Human Reproduction, 12(8): 1742–1749.
Morbeck DE. (2015). Culture media and laboratory conditions: role in the regulation of early human embryo development. Seminars in Reproductive Medicine, 33(2): 103–110.
In conclusion, frequent incubator door openings can have a significant impact on embryo development and viability. Therefore, it is essential to minimize the frequency and duration of door opening and take steps to maintain stable culture conditions inside the incubator. By doing so, embryologists can maximize the chances of successful embryo development and improve the outcomes of ART procedures.
