IVF cells, also known as in vitro fertilization cells, are cells that are used in the process of in vitro fertilization. This process involves the fertilization of an egg outside of the body, usually in a laboratory setting. The egg is then implanted into the uterus of the woman who wishes to become pregnant. OVA, which is the answer to the crossword puzzle, stands for oocyte, which is another name for an egg cell.