How do we decide how many embryos to transfer ?

Saiprasad Gundeti, Senior Embryologist, Malpani Infertility Clinic

There are multiple variables which need to be considered while deciding how many embryos to transfer.
When we decide about the number of embryos to transfer , our aim is to :

1. Select Top Quality Embryo(s) for transfer
2. Maximise the chances of pregnancy.
3. Minimise the risk of failure.
4. Minimise the risk of multiple pregnancy.

Each country has its own policies depending upon their patient population, their healthcare system and their laws.
In Scandinavian countries , not more than one embryo is allowed to be transferred.
In such countries, doing a Day 5 transfer is ideal.

Top Quality Day 5 Embryo

That’s not the case in India where we can transfer multiple embryos. However, we need to individualise this decision for each patient ! More is not always better – and transferring too many embryos increases the risk of a high order multiple pregnancy.

We need to be flexible !

For example, when doing a Day 3 Embryo Transfer for a young patient who is doing her first IVF cycle, we need to consider transferring only 2 embryos, as there are high chances of a pregnancy even with 2 embryos.

2 Top Quality Day 3 Embryos

At Malpani Infertility Clinic, we use the following guidelines. These are rules of thumb – the patient needs to make the final decision ! While the present fashion seems to be to push for a SET ( single embryo transfer) for all patients, this is a complex decision – especially when patients are paying large amounts of money for their IVF treatment. And for many IVF patients, twins are a welcome bonus as they represent their chance to create an instant family !

While it’s quite easy to make decisions when we have good quality embryos, it’s much harder to do so when the embryos are of poor quality. While it’s not necessarily true that transferring more embryos increases the chances of success when the embryos are of poor quality, patients are understandably reluctant to throw away their embryos ! This is especially true when patients have failed multiple IVF cycles in the past . Their logic is – even if the embryo has a poor chance of becoming a baby after transfer, at least it’s better than the zero chance if I do not transfer it. This can be a difficult call to
make !

DAY	Criteria	Age <>	Age > 38	Previous Failures
Day 2	Good Embryo Quality For e.g. 4 x 4-Cell Grade A	3 Embryos	4 Embryos	4 Embryos + 1 Embryo
	Slow Growing embryos. For e.g. 2 Cell Grade A 3 Cell Grade A	4 Embryos	5 Embryos	5 Embryos + 1 Embryo
	Poor Embryo Grade For e.g. 4-Cell Grade C	5 Embryos	6 Embryos	5 Embryos + 1 Embryo
Day 3	Good Embryo Quality For e.g. 8-Cell Grade A 6-Cell Grade A	3 Embryos 3x 8-Cell Grade A	4 Embryos	4 Embryos + 1 Embryo
	Slow Growing embryos. For e.g. 4 Cell Grade A 3 Cell Grade A	4 Embryos	5 Embryos	5 Embryos + 1 Embryo
	Poor Embryo Grade For e.g. 8-Cell Grade C	4 Embryos	5 Embryos	5 Embryos + 1 Embryo
Day 5/6	Good Embryo Quality For e.g. Grade A Blastocyst	2 Embryos	3 Embryos	3 Embryos + 1 Embryo
	Slow Growing embryos. For e.g. Morulae	2-3 Embryos	4 Embryos	3 Embryos + 1 Embryo
	Poor Embryo Grade For e.g. Grade C Blastocyst	3-4 Embryos	4 Embryos	3 Embryos + 1 Embryo

Note : The number of embryos to transfer :
1) may be increased if the endometrial thickness is poor
2) may be reduced if the patient is young