Advances in cryopreservation technology have transformed the landscape of fertility treatment over the past decade. At New Hope IVF Hospital in Sharjah, embryo freezing and frozen embryo transfer (FET) have become integral parts of our IVF program, offering patients flexibility, improved safety, and in many cases, higher success rates than transferring a fresh embryo immediately after retrieval.
What Is Embryo Freezing?
Embryo freezing, medically known as cryopreservation, is the process of preserving embryos at very low temperatures for future use. Most clinics, including New Hope IVF Hospital, use a technique called vitrification, an ultra-rapid freezing method that prevents the formation of ice crystals within the embryo’s cells. Vitrification has largely replaced older, slow-freezing methods because it results in significantly higher embryo survival rates after thawing.
Embryos can be frozen at different stages of development, most commonly at the blastocyst stage, which is typically reached five to six days after fertilization. Once frozen, embryos can remain viable for many years without any known deterioration in quality.
Why Patients Choose Frozen Embryo Transfer
There are several medical and practical reasons a fertility specialist may recommend freezing embryos rather than proceeding with a fresh transfer.
Reducing the risk of ovarian hyperstimulation syndrome (OHSS): Patients who respond strongly to ovarian stimulation medications are at higher risk of OHSS. Freezing all embryos and delaying transfer until hormone levels normalize helps protect the patient’s health.
Allowing time for genetic testing: When preimplantation genetic testing (PGT) is performed, embryos must be frozen while laboratory results are being analyzed, typically taking one to two weeks.
Optimizing the uterine lining: In a fresh IVF cycle, high hormone levels from ovarian stimulation can sometimes make the uterine lining less receptive to implantation. Freezing embryos allows the uterus to return to a more natural hormonal state before transfer, which research suggests may improve implantation rates for some patients.
Planning and flexibility: Some patients choose to freeze embryos for personal, medical, or scheduling reasons, allowing them to plan a pregnancy at a time that suits their circumstances.
The Frozen Embryo Transfer Process
When a patient is ready to proceed with FET, our team prepares the uterine lining using one of two main approaches: a natural cycle, which relies on the body’s own ovulation, or a medicated cycle, which uses estrogen and progesterone to prepare the endometrium. Throughout this preparation, we monitor the uterine lining thickness and hormone levels closely using ultrasound and blood tests.
Once the lining reaches the optimal thickness and pattern, the previously frozen embryo is thawed and transferred into the uterus using a thin catheter, a quick and generally painless outpatient procedure. A pregnancy test is typically performed about ten to fourteen days later.
Safety and Success Rates
Extensive research has shown that vitrified embryos have thaw survival rates exceeding ninety percent in experienced laboratories. Pregnancy rates from frozen embryo transfers are now comparable to, and in some patient groups higher than, those from fresh transfers. Children born from frozen embryos have not shown increased health risks compared to those from fresh transfers, providing reassurance to patients considering this option.
Why This Matters for Your Fertility Journey
Embryo freezing gives patients greater control over the timing and safety of their treatment. It also means that a single egg retrieval can potentially result in multiple opportunities for pregnancy, reducing the physical and emotional burden of repeated stimulation cycles.
At New Hope IVF Hospital, our embryology laboratory follows strict quality control protocols to ensure the highest standards of embryo storage and handling. If you have questions about whether frozen embryo transfer is right for your treatment plan, our fertility specialists are here to guide you through every step, from freezing to transfer to, we hope, a positive pregnancy test.