After fertilization is confirmed, embryos are cultured in incubators. Embryologists in the lab carefully control factors such as nutrients, humidity, temperature, and exposure to light.
During this time, some embryos will stop developing, but the ones that continue to develop will reach the blastocyst stage by culture day five or six. Approximately 25 to 50 percent of fertilized eggs will become blastocystsand will be of high-enough quality for transfer to the uterus or cryopreserve.
The case number and patient’s last name are on the incubator location label and etched on the bottom of each petri dish that the embryos are cultured in. The ID of the embryologist doing the daily embryo observation and the time of the observation are on the IVF laboratory worksheet.