During the handling of Oocytes and Embryos they must be protected from physical and chemical changes, specifically:

• Culture medium osmotic concentration and pH
• Temperature fluctuation
• Air cleanliness

Culture Medium Osmotic Concentration and pH

Culture media used for human IVF has advanced over recent years and ‘sequential culture media’ comprises of a range of media and buffers that are used to optimise the support level to each stage of the process.

Human embryos show better development, and implantation potential, if the oxygen tension is reduced from that in normal air. Correct use of all culture media requires the use of special atmospheres that are, at a minimum, enriched in carbon dioxide.

If culture medium is exposed to air with a low humidity, evaporation loss from the medium will increase medium osmolality and affect the pH.

Temperature

The female germ cell or oocyte is particularly sensitive to alterations in temperature. Changes in temperature affect trans-membrane transport and many intracellular metabolic processes. Human oocytes and embryos must be held as closely as possible at a stable 37 °C. Temperature changes and evaporation affects the pH value of the sample.

Air Quality

Embryos are highly sensitive to toxic chemicals due to their high metabolic and cell division rates. IVF laboratories and procedure rooms should be designed to minimise and control volatile organic compounds (VOCs) and other air pollutants.

HEPA filters are used to control airborne particulates but are not effective at removing VOCs as these gases molecules can readily pass through the filter. Specially designed activated carbon filters should be fitted to the air supply system to remove VOCs.