
Embryo at the 8-cell stage of development. © CUSM
In vitro fertilization (IVF) is a procedure for achieving fertilization in a laboratory. Once sperm cells and eggs are collected, they are brought together in vitro, meaning in a laboratory. The sperm cells then fertilize the egg to produce an embryo. The embryo is then placed in conditions that allow cells to divide. Once the embryo is sufficiently developed, it is ready to be transferred.
The following medical procedures are needed for in vitro fertilization:
- Ovarian stimulation
- Egg collection or egg donation
- Sperm collection or sperm donation
- Forming and storage of embryo
- Freezing and transfer of embryos
Intracytoplasmic Sperm Injection

Intracytoplasmic Sperm Injection. © CUSM
For some cases of infertility, fertilization can be assisted. Intracytoplasmic sperm injection is an in vitro fertilization technique that consists of injecting a single selected sperm cell into the egg.
Freezing and Storage of Embryos
The process of in vitro fertilization generally produces several embryos. However, only 1 embryo is usually transferred into the woman’s uterus. The rest are frozen and stored for future use.
When the number of embryos produced is higher than what the couple needs, the extra embryos can be donated or destroyed. The couple’s consent is always required for both donation and destruction.
Last update: December 11, 2017