With exceptional improvement in advanced reproductive technologies, both fresh and frozen embryo transfers (FETs) have been facilitated. Nowadays, FETs are preferred for delayed pregnancy due to personal career goals, certain health condition and other factors. However, both are used regularly for IVF procedures. You can consult an IVF centre near you to learn about FETs.
For infertility treatment, both fresh and frozen embryo transfer are incorporated to achieve pregnancy. But there are certain differences between the two procedures. The major difference is that while fresh embryo transfer takes place within a week of retrieval, frozen embryo transfer uses the embryo weeks or years later, which is preserved through cryopreservation for future use.
Difference Between Fresh and Frozen Embryo Transfer
In IVF treatment, embryo transfer is the last and final procedure before pregnancy occurs. But choosing between fresh and frozen embryo transfer can feel difficult, as both procedures serve the same purpose with significant differences. In fresh embryo transfer, the best and healthiest embryos are implanted back to the uterus withing few days of egg retrieval, leading to pregnancy. In frozen embryo transfer, the retrieved embryo is stored in liquid nitrogen and returned in weeks or sometimes in a year to achieve pregnancy.
Here is an overview of both embryo transfers:
Fresh Embryo Transfer: During the IVF procedure, the fresh embryo transfer typically occurs faster. Initially, the patient with infertility is given a hormonal injection for ovarian stimulation by the specialist. After the stimulation is provided, a patient needs to wait 10-14 days for egg retrieval when the doctor collects the eggs ovulated by the stimulation.
A surgeon inserts a fine catheter inserted through the vagina of the patient to collect the eggs and fertilise them with collected sperm in a petri dish in a controlled lab environment. The embryo is monitored for 5–6 days during blastocyte stage before implantation. The patient is kept on medication for endometrial readiness to receive the embryo once it is mature. During this phase patient can opt for. Preimplantation Genetic Testing to check for any genetic abnormalities in the embryo before transfer, which requires freezing. After that, the embryo is implanted in the uterus through a thin tube, leading to pregnancy.
However, in a fresh embryo, the risk of OHSS (Ovarian Hyperstimulation Syndrome) increases, especially in patients with PCOD (Polycystic Ovarian Syndrome), which involves hormonal injections causing ovaries to swell, become painful, and leak fluids in abdome,n creating difficulties in pregnancy and success rate.
This procedure costs higher particularly when a cycle fails, and new stimulation is required. Patients with limited embryos, no OHSS risk or younger in age are ideal candidates for the fresh embryo transfer option. The success rate depends on several factors such as age, lifestyle, egg quality and health condition of the patient.
Frozen Embryo Transfer: In frozen embryo transfer, the initial procedure remains the same as the fresh embryo transfer till fertilisation. It involves ovarian stimulation and collecting the eggs ovulated by the stimuli, and under doctors supervision, the egg is fertilised with healthy sperm until it becomes a mature embryo. The embryos are vitrified in an utra-fast freezing step that prevents ice crystals and stored at -196° C.
After weeks or months, sometimes a year, when the patient is ready for transfer, she is given drugs to stimulate the natural menstrual cycle and the FET date iscoordinated to maximise implantation. However, if the patient wishes to check the embryo’s chromosomal or genetic disorders, then PGT (Preimplantation Genetic Testing) can be performed shortly after egg retrieval. Once the testing is complete, the specialist chooses the healthiest embryo for transfer to improve pregnancy success.
The frozen embryos can be used for additional pregnancies years later, as embryos can be stored indefinitely. In this procedure, the risk of OHSS is much lower, leading to an increased success rate of pregnancy. It is less costly than a fresh embryo transfer, requiring lining medicines only. However, it may require additional visits to the clinic with flexible timing. Patients needing genetic testing, suffering from PCOS(Polycystic Ovarian Syndrome), wishing to preserve fertility due to age, cancer teatment and other reason are can opt for frozen embryo transfer.
Success Rate: In both fresh and frozen embryo transfer, there are multiple factors to consider for their respective success rate. Factors playing a crucial role in deciding a fresh embryo transfer and frozen embryo transfer include the age of donors, age during freezing, egg and sperm quality and overall health condition.
Though there are certain benefits of choosing frozen embryo transfer as it is less costly, reduces physical and mental strain, provides an opportunity to preserve fertility for the future and plan pregnancy accordingly. However, the aforementioned factors, mainly age, play a determining role in the success rate of the treatment. You can consult a learned professional to understand IVF fresh vs frozen cycle success rates to make an informed decision.
Final Words
Despite some differences, both fresh and frozen embryo transfer serve the same purpose, which is achieving pregnancy. When deciding which option to choose, it depends on extensive analysis of the patient’s age during freezing the embryo or using fresh embryos, the number of embryos, the medical history, hormonal profile, certain health conditions such as PCOS, endometriosis or others and quality of eggs or sperm for fertilisation and possible risks
Only when every criterion is matched according to the health condition can one choose a fresh or frozen embryo transfer as per the consultation with a specialist. You can visit a trusted IVF centre near you to get the best advice on which transfer would be suitable for you, regardless of what you consider or what you read worldwide.