Use of mineral oil in IVF culture systems: physico-chemical aspects, management, and safety

The study aims to summarize current knowledge on the use of oil in embryo culture systems, with a focus on proper management of different types of oil and possible impact on culture systems.PubMed was used to search the MEDLINE database for peer-reviewed English-language original articles and reviews concerning the use of oil in embryo culture systems. Searches were performed by adopting "embryo," "culture media," "oil," and "contaminants" as main terms. The most relevant publications were assessed and discussed critically.Oils used in IVF are complex mixtures of straight-chain hydrocarbons, cyclic and aromatic hydrocarbons, and unsaturated hydrocarbons, whose precise composition influences their chemical and physical properties. Possible presence of contaminants suggests their storage at 4 °C in the dark to prevent peroxidation. Washing, generally performed by manufacturers prior to commercialization, may remove trace chemical contaminants. Oils reduce evaporation from culture media at rates depending on their chemical physical properties, culture system parameters, and incubator atmosphere. Contaminants - mainly metal ion and plastic components derived from refinement processes and storage - can pass to the aqueous phase of culture systems and affect embryo development.Oils are essential components of culture systems. Their original quality and composition, storage, handling, and use can affect embryo development with significant efficiency and safety implications.