INTRA CYTOPLASMIC SPERM INJECTION Olympus ICSI Microscope Intra-cytoplasmic sperm injection (ICSI) is a procedure consisting of injection of a singleRead more
Family Clinic provides various fertility and child care services
Frequently Asked Questions about Intrauterine Insemination (IUI) BY DR. KAVITA MANTRY Infertility Specialist IUI FREQUENTLY ASKED QUESTIONS Q: What isRead more
Frozen embryo transfer (FET) is an innovative technique used to increase your chances of becoming pregnant. To better understand FET, it helps to take a brief look at in vitro fertilization (IVF). During this procedure, egg cells are surgically removed and are fertilized by sperm collected from the patient's partner or a donor. Once fertilized, the embryo can immediately be transferred to the woman's uterus. This procedure is also known as fresh embryo transfer, and most women undergo induction of ovulation to further increase the chances of conception.
Using frozen embryo transfer, the embryos are cryopreserved in a process called vitrification, a process of flash freezing that prevents crystallization. When a woman experiences ovulation naturally, the frozen embryo can be thawed and placed in the uterus.
There has been a recent trend away from traditional "slow freezing" technology that has been used since the 1980's. The newer vitrification method for IVF embryo freezing is becoming a much more widely used technology.
How are frozen-thawed embryo transfer cycles managed?
There are different protocols for FET cycles. That is true for both "natural cycle" FETs and for "hormone replacement cycle" frozen-thawed embryo transfers.
At the Family Clinic, we use hormone replacement cycles because they have better success rates. However, some clinics offer a natural cycle FET approach. Success rates are higher with hormone replacement, or "controlled" FET cycles.
Hormone replacement cycle, controlled FET
Pregnancy success rates with FET - frozen embryo transfers:
Success rates for frozen embryo transfer cycles vary considerably by the program handling the case. Some programs have low pregnancy and live birth from their frozen embryo transfer cycles while other IVF programs have live birth rates of over 50% per transfer procedure in women under 35 for frozen-thawed transfer cycles.
As more IVF programs vitrify rather than slow freeze the spare embryos, FET success rates across the US should improve significantly
Our success rates for frozen transfer cycles
Blastocyst implantation in an FET cycle
Embryo implantation after frozen blastocyst transfers (FET) can be slightly delayed compared to that seen with fresh blastocyst transfer. This is sometimes referred to as "late implantation", or delayed implantation.
However, the embryo implantation process is not different enough to warrant changing the timing of the blood pregnancy test. Frozen blastocyst transfers should have hatching and the beginning of implantation by about 1-3 days after the FET.
Early pregnancy detection following blastocyst transfer is possible with a sensitive blood assay for HCG hormone by about 9 days after a fresh or frozen blastocyst transfer.
A urine HPT (home pregnancy test) can be done by 10 to 12 days after blastocyst transfer (fresh or frozen), if it is a sensitive, high quality test kit.