With In Vitro Fertilisation (IVF), the ovaries are stimulated to produce more eggs than in a natural cycle. The eggs are retrieved in theatre under sedation, inseminated with freshly prepared sperm and cultured overnight. Fertilisation is checked the next morning and embryos are cultured for two, three or five days (see Embryo stages). Scoring of the embryos is performed and the highest scoring embryos are selected to be transferred back to the uterus.