Frozen embryo transfer allows for synchronized implantation & endometrial development as delaying the embryo transfer until a later menstrual cycle allows the regular production of hormones. This helps to normalize estrogen & progesterone production before proceeding the embryos are transferred and therefore have a better chance of pregnancy.
Otherwise, worsening ovarian hyperstimulation syndrome and elevated progesterone during ovarian stimulation could lead to desynchronization of the embryo and the uterus lining.
In a frozen embryo transfer cycle, the embryo has been previously created, sometimes even years earlier, and then will be placed into the uterus. The freezing of the embryos allows the body to recover from IVF. Once the body has had done so and has returned to a more normal cycle, the embryos are thawed and implanted into the uterus with the ideal endometrial conditions.
Frozen Embryo Transfer vs. Fresh Embryo Transfer
Fresh and frozen types of embryo transfers refer to the mode of transfer. In the case of fresh embryo transfer, the eggs would have been cultured for a period of 1-2 days after fertilization. These are then ready for transfer and deposited into the womb. A frozen embryo transfer is when unused embryos are saved for later use. These are frozen and will require to be thawed before deposition in the womb.
While both fresh and frozen embryo transfers have been successful in their own way and depending on the condition of the patient & their needs doctors prescribe either one of the two modes – overall data suggests that frozen embryo transfers are slight more successful than fresh ones. However, that alone is not the only parameter to arrive at a decision, as many across the field of fertility continue to debate the issue with vigor.
Each case is required to be ascertained on its own merit, and several experts warn against formulating a generic view. There are primarily two main factors that determine the success or failure of the embryo transfer – quality of embryos and the receptibility of the uterus.
Reproductive medicine specialists continue to advise patients based on a variety of factors age, stimulation response, and ovulatory versus anovulatory status into account to make the recommendation that’s best for each patient.
What is the Success Rate of a FET in IVF?
In generic terms, the chances of getting pregnant with a fresh or frozen embryo may be the same. However, advancing technologies have brought about a lot of chances and improvements in the process of freezing and storing embryos which now makes it much easier for patients to opt for a frozen embryo transfer.
Previously, before the advent of vitrification, the process of freezing the embryo was too slow and too ineffective. It did more harm than good to the embryo and therefore it was an overwhelmingly better choice to go for fresh embryo transfers. However, this has changed considerably now, and it is now possible to freeze the embryo a lot more efficiently and without compromising the quality.
The uterine receptivity or uterine quality plays an equal role in the success or failure of the embryo transfer. The medications prescribe had a propensity in the past made it difficult for doctors to prepare the embryo simultaneously as the eggs had been harvested, while this has now changed considerably, it is important to underline that it is best to take a patient-specific view on this rather than formulate blanket opinions.
Am I a candidate for FET?
This is a question that is specific at the individual-level. A lot of factors will have to be considered prior to zero in on the patient’s suitability for either frozen or fresh embryo transfer. An increasingly large number of patients are now ideal for a frozen transfer, while in some specific cases the doctor may advise a fresh transfer. Consult your reproductive medicine specialist for a thorough and complete evaluation before ascertaining the mode of transfer that is best for you.