In vitro fertilization means fertilization outside of the body. The female partner receives external hormones so that more follicles form in the ovaries. The egg cells grow within these follicles. Eventually, they are removed from the follicles and united with the partner’s sperm cells under laboratory conditions. Therefore, the fertilization occurs outside of the organism. After the embryos have developed to a multicellular stage they are implanted (maximum 2 to 3 embryos) into the uterus where they continue to develop.
The in-vitro fertilization treatment consists of several steps: