In-vitro fertilisation (IVF). Artwork showing a human egg cell (ovum) being fertilised by the injection of a sperm cell. The ovum is being held in place by gentle suction using a micropipette (left), while the sperm injection is being done with an ultra-thin needle (right). This procedure, known as intracytoplasmic sperm injection (ICSI), is used when there are problems with sperm motility or low sperm count. The sperm cell fertilizes the egg cell and the zygote that forms is cultured until it reaches an early stage of embryonic development. It is then placed in the uterine wall, allowing pregnancy to commence.