IVF egg preparation. Image 1 of 3. Light micrograph of a human egg cell (upper right) during preparation for in vitro fertilisation (IVF). The egg cell (ovum) is surrounded by its corona radiata layer of cells. The corona radiata normally nourishes the egg, but is removed for IVF to facilitate fertilisation. For IVF, fertility drugs are given to stimulate the ovaries to produce more eggs. These are fertilised with sperm in a laboratory. If this is successful, a resulting embryo is implanted into the mother's uterus and pregnancy continues normally. For a sequence showing this decoronisation, see images M802/181-183. Magnification unknown.