For some couples who are struggling with infertility, the most effective treatment might be in vitro fertilization. In an IVF cycle, both an egg and sperm are removed from the body and used to create an embryo in a lab setting. Embryos can be transferred to the woman’s uterus right away in hopes of a successful pregnancy, or they can be frozen for many years, thawed and transferred at an optimum time for conception.
Good candidates for IVF might be couples with unexplained infertility, women who don’t ovulate on their own, or couples where the male partner has sperm abnormalities. For more about IVF and who might qualify, click here.
The Basics of a Fresh Embryo Transfers
In an IVF cycle, a woman takes fertility medication to stimulate egg production. When they are mature, her eggs are retrieved during a simple outpatient procedure, and combined with sperm to facilitate fertilization. The resulting “fresh” embryos can then be transferred to the woman’s uterus within 5 days or less.
During a fresh transfer, the woman’s endometrial lining is built up (or prepped and ready for pregnancy) due to estrogen production during ovulation stimulation.
How Frozen Embryo Transfers Work
A frozen embryo transfer takes place during a separate, later IVF cycle. It’s usually within one to two months, but it can be a year or longer after the retrieval.
Because the woman does not need to stimulate egg production prior to a frozen embryo transfer, her endometrial lining must be built up with the help of estrogen supplements in the form of pills, patches or injections.
Since she does not have to undergo either ovulation stimulation or the process of egg retrieval, a frozen IVF transfer is usually less costly, less stressful and less invasive than a fresh transfer.
Why Choose a Frozen Embryo Transfer?
There are many reasons couples choose to postpone their IVF transfer and freeze one or more of their embryos. Maybe the couple is not at a place in their lives where they are ready to start a family due to career choices or other factors, but they want to have the option later. Or maybe they wish to do genetic testing on the embryos to rule out possible complications before trying to become pregnant.
The woman’s doctor may advise against a fresh transfer for medical reasons. For example, during the stimulation or egg retrieval phase of her IVF cycle, she may have become at risk for risk for ovarian hyperstimulation or other conditions that would make the transfer less successful, such as inadequate endometrial lining or abnormally high estrogen levels.
Benefits of Frozen Embryo Transfers
In the past, embryos were frozen slowly, which allowed ice crystals to form on them. Those crystals could cause damage to the embryos during the thawing process.
Today, thanks to new technology, embryos are vitrified — plunged in liquid nitrogen — which freezes them very quickly, allowing no time for ice crystals to form. This process helps prevents damage to the embryos at the time of thawing, helping to ensure they are viable. In fact, nearly 99% of all vitrified embryos survive the freezing-thawing process.
Success Rates of Fresh vs. Frozen Embryo Transfers
The success rate to become pregnant with a frozen IVF transfer is at least as high as with a fresh transfer, possibly even higher. Both fresh and frozen embryos present the same, minimal risks for pregnancy complications and genetic abnormalities. In women under age 35, the average chance for achieving a successful pregnancy with one IVF cycle is about 45-50%.
Contact Your IVF Expert
If you’re interested in IVF and want to know more about fresh vs. frozen embryo transfers, call us for a consultation at (502) 897-2144.