What Does
Freeze All Cycle Mean?
A freeze all cycle refers to a cycle of in vitro fertilization (IVF) in which the resulting embryos are frozen for later use rather than transferred right away (fresh transfer). The name ‘freeze all cycle’ refers to the fact that all of the embryos created during a cycle of IVF are frozen in contrast to a fresh transfer where only the extra embryos are frozen.
A freeze all cycle is also called a delayed frozen embryo transfer.
FertilitySmarts Explains Freeze All Cycle
Depending on several factors, individuals or couples undergoing IVF can choose to either have the resulting embryos transferred to a uterus 3 days after fertilization, 5 days after fertilization, or have them frozen for later use. If the embryos are transferred on day 3 or 5, it is referred to as a fresh transfer. When the embryos are frozen for later use, it is called a freeze all cycle.
A freeze all cycle may be indicated for many reasons including:
- To preserve embryos before a medical procedure that may impact fertility, such as chemotherapy.
- To prevent the risk of development of ovarian hyperstimulation syndrome (OHSS) in high-risk women.
- To allow time for preimplantation genetic diagnosis or screening.
- Based on the preference of the healthcare professional and/or patient(s).
Healthcare professionals or patients may prefer a freeze all cycle over a fresh transfer due to the impact of ovarian stimulation on the quality of the uterine lining. Before an egg retrieval, a woman’s ovaries are stimulated to mature multiple follicles using a process called controlled ovarian stimulation (COS). Some evidence suggests that COS causes changes to the endometrial lining of the uterus that negatively impact pregnancy rates as well as maternal and fetal outcomes.