IVF is the most expensive and effective fertility treatment option. Unlike IUI and IVC, IVF involves fertilization of eggs with sperm outside the body, followed by extended embryo culture in the laboratory. Embryos that develop into quality blastocysts are vitrified or frozen in liquid nitrogen on days 5, 6, and sometimes 7. It is recommended to schedule a frozen embryo transfer (FET) rather than a fresh embryo transfer (ET) to improve pregnancy success; however, I encourage you to discuss your options with your doctor given your circumstances.