What is Freeze All IVF Cycle


Conventionally Fresh Embryo Transfer in an IVF or ICSI cycle was done on Day 3 or Day 5 after OPU (OPU – Ovum Pick Up day is considered Day 0). This is known as a Fresh IVF ET Cycle.

Another viewpoint is that the environment of the uterus is not suitable for Embryo Transfer in a stimulated cycle. This is because the hormone levels in a stimulated cycle are very high and unnatural as compared to a natural cycle. Such high levels of hormone (Estrogen) are not good for implantation, because of which success rates in a stimulated cycle is less. In short, Ovarian Stimulation has an adverse impact on implantation rates in IVF / ICSI cycles.

Studies suggest that the modifications in uterine environment that occurs during a Controlled Ovarian Stimulation (Stimulation to ovaries using drugs to produce follicles), may be detrimental to the IVF outcome after Fresh Embryo Transfer compared to a Frozen Embryo Transfer cycle.

In older days where the cryopreservation of embryos was not as robust, clinicians were apprehensive of cryopreserving good embryo’s hence wanted to transfer them in a fresh IVF ICSI cycle. However in the past few years we have seen significant improvement in both Cryopreservation media and protocol, resulting in nearly 100% embryo and oocyte survivability. This has given confidence to Infertility Specialists and today, most of the clinician’s prefer a Freeze All IVF Cycle for their patients.

Q. What is Freeze All IVF Cycle?
In a Freeze All cycle, all the good Embryo’s formed during the IVF-ICSI cycle are cryopreserved for later transfer. Usually the best embryo is kept for the first transfer
Q. Should Freeze All cycle be done for all Patients?
There is evidence beyond doubt that for patients who have higher number of retrieved oocytes, Freeze All IVF cycle with a frozen embryo transfer will give better pregnancy rate than a Fresh Embryo Transfer.

However, patients who have less number of retrieved oocytes, have similar success rate of a Blastocyst transfer on either fresh frozen cycle. Patients who have extremely low number of oocytes (3 or less) should be ready to accept that the number of good quality embryo formed could be as less as one. And in that case, it might be best to undergo a Freeze All IVF Cycle so that you stand the best chance.

At times, even after best effort and intention, especially for patients with extremely low number of oocytes or poor quality of oocytes, no embryos are formed after culture in IVF lab. In such a case no embryos will be transferred and patients must be ready to accept the situation and be prepared to try again.

The Embryo transfer Plan of a patient is usually a very dynamic decision, which is based on many parameters like number of follicles retrieved, number of oocytes fertilized, number of good quality embryo’s formed on Day 3 etc. The dynamic nature of the embryology parameter makes it very difficult to predict the Embryo transfer plan for most cases before knowing the actual status of the Embryos. Hence IVF Clinics at times may ask you to enquire about the embryo’s formed on Day 3 and decide if you wish to undergo a fresh Embryo transfer or wish to Freeze All for later use.
Q. When are Freeze All Cycles advised?
  • Cancer patients, who may have undergone IVF cycle prior to chemotherapy in order to preserve embryos for later use.
  • In order to prevent risk of OHSS (Ovarian Hyper Stimulation Syndrome), in patients with high number of follicles and as a result high level of estradiol, Freeze All cycle is recommended. In such patients, an Embryo transfer is done after the ovaries have reached a normal size and function.
  • To allow genetic screening of Embryos using PGD or PGS. PGD or PGS is done in cases where either one or both partner have a risk of passing genetic disorders like thalassemia, sickle cell anaemia, cystic fibrosis etc to their progeny. In such a case, embryos are cultured till blastocyst stage, a few cells from the blastomere are extracted using a Laser and these cells are sent to special genetic labs for screening. Embryos are then frozen until the test result of PGS or PGD are received, which usually takes anywhere from 7 days to 5 weeks depending on the type of test. Once the results arrive, frozen embryos that have been identified as the ones that are genetically normal, shall be used to transfer in a Frozen Embryo Transfer cycle.
Q. Is Freeze All IVF Cycle Cost Effective?
Most patients who undergo IVF ICSI cycle are able to produce enough oocytes to produce 2 or more Blastocysts, hence there is not too much difference in the cost of cryopreservation of one extra Blastocyst for a Freeze All Cycle as compared to transferring single blastocyst in a Fresh IVF cycle. In case a patient only has one viable embryo, then Freeze All cycle results in additional cost to cryopreserve and then perform a Frozen Embryo Transfer. However, the chances of conception in a FET cycle is usually more as compared to a fresh transfer, hence it’s worth spending that extra amount.
To summarize, choose a center where your Embryo Transfer Plan is individualized based on your case.
This short video has been filmed in our lab by our Embryologist's to capture the entire process of Embryo Freezing
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