Fresh vs Frozen Transfers
Women who pursue in vitro fertilization (IVF) to have a baby have many important decisions throughout the process. Selecting between a fresh and frozen embryo transfer (FET) can make a difference in pregnancy outcomes. Understanding the pros and cons of different transfer options can help fertility patients feel empowered to make the right choice.
The IVF cycle
Women should understand the entire IVF cycle before deciding whether to pursue a fresh or frozen transfer. Although each case is unique, most patients will start IVF by receiving medications designed to stimulate the ovaries to produce multiple eggs. Growth of the eggs will be monitored closely, and a retrieval will then be scheduled at a pivotal time in the cycle. Once the eggs are retrieved, the specimen can be stored separately or combined with sperm in the lab to create an embryo. The embryo is then transferred back into the uterus or stored.
The term fresh connotes images of clean and new, and many women often think a fresh embryo transfer is the best choice. However, the reality is a bit more complicated, and a fresh transfer isn’t always best. With a fresh transfer, the egg is retrieved, fertilized, and transferred back into the uterus within a single cycle. This approach saves money and can result in a faster timeline to pregnancy but isn’t always as successful. Having just received hormone medication to stimulate egg growth and undergo a retrieval, the body may not be physically ready for a transfer as the uterine environment is still in recovery mode.
Benefits of a frozen transfer
With a frozen embryo transfer, the egg is retrieved in 1 cycle and transferred back in a subsequent cycle. This approach is often preferred since it allows time for hormone levels to restabilize and for the body to be ready to accept the implanted embryo. Recent studies show that live birth rates are significantly higher in women who opt for FET to get pregnant.
Risks of defrosting
Some patients may worry about the potential risks of the unfreezing process. Although rates vary depending on the original health of the egg, the clinic where the eggs are stored, and how long the specimen has been frozen, recent statistics show that 74% of eggs survive the thawing process. This means most frozen eggs will do just fine, but there are some situations where a fresh transfer may be safer. For example, if a woman only has 1-2 frozen eggs and no plans for another retrieval, a fresh transfer may be a better idea to increase overall chances of success.
Ultimately, the fertility patient should discuss the pros and cons of each option with a trusted healthcare provider before deciding whether to pursue a fresh or frozen transfer. Both approaches can result in a healthy baby, but a frozen transfer may allow the uterus the necessary time to reset, increasing the overall chances of success.