Step 4: Insemination of Eggs and Development of Embryos in the Laboratory

After the eggs have been retrieved, they are immediately transferred to the adjacent laboratory for identification, evaluation, and preparation for insemination. In the process of collecting follicular fluid, usually many eggs are obtained. We recommend that all of the eggs be inseminated to maximize the number of embryos available for implantation. The prepared sperm is added to each egg, and they will be allowed to incubate for 2 hours under controlled laboratory conditions. In some instances, micro-injection of an individual sperm into each oocyte will be performed in a procedure called Intracytoplasmic Sperm Injection (ICSI). The next day, each egg is evaluated for evidence of fertilization.

The fertilized eggs will be allowed to develop for one or more days under controlled laboratory conditions before they are placed inside the woman's uterus. Depending upon the patients' wishes, some fertilized eggs or embryos may be frozen and stored for future use in a process called cryopreservation. Before embryos are transferred to the uterus, the woman will receive progesterone which has been shown to create a more favorable environment for embryos.