It is a common perception that fresh embryo transfers are more successful than frozen embryo transfers. The thinking behind this attitude could be that highest quality embryos are transferred during the fresh cycles, while the rest, less viable ones are saved for the future attempts. Another possible issue is that people do not fully understand what freezing actually means and think that it may affect the embryo quality. As the matter of fact, this way of thinking is not correct.
The belief that fresh embryo transfer has definitely higher success chances than the frozen, is far from accurate.
Fresh embryo transfer
Before the cycle, female body should be prepared for the egg retrieval. Ovaries get stimulated in order to produce extra eggs. The medications used for the procedure are not light for the body as they are interfering with the hormones. If the first cycle is not successful or intended parents want more children, with no frozen embryos in storage, it will be necessary to go through the stimulation and egg retrieval processes once again. Definitely not the best practice.
While the hormone levels are being manipulated with every new retrieval procedure, it is important to also consider that each fresh cycle can cost even up to 10 000 USD, depending on the location and clinic.
Frozen embryo transfer
Frozen egg transfer requires preparation too – the uterine lining has to thicken in order to be ready for receiving the embryo. The medications used for the process are less expensive than the ones used while the retrieval and fresh cycle. Additionally, they are much less demanding of the body.
When the embryo transfer occurs a while after the stimulation and retrieval, female body gets the chance to normalize hormone levels and get back to natural state, which is more suitable for the conception. A lot of researchers argue that this can have a positive effect on baby and reduce the chances of low birth weight and preterm labour.
A lot of intended parents find it very comfortable, not having to worry about the egg production and the repetition of the retrieval procedure. With the frozen eggs in storage, intended parents have the ability to plan the date of their cycle months in advance and prepare for it appropriately.
As medical technologies have advanced a lot, freezing techniques have altered and advanced too. Ultra rapid freezing method results in higher success rates than the slow freezing method that was used back in the days.
Important notice for the intended parents is that freezing does not change or affect an embryo. In fact, embryos are kept from aging and are conserved the way they were before freezing. This is also the hint that the chances of success can not be lower in comparison to fresh embryo transfer.
In terms of success, there are no clear evidences in advantage of fresh or frozen egg cycles, however, the same applies to the disadvantages too.
The best practice
In order for the embryo transfer to be most practical, both medically and financially, it would be reasonable to stick to the following route : after the egg retrieval, perform fresh embryo transfer and in case of further cycles, use the frozen ones. Repeated cycles should be planned with the storage of frozen embryos.
Before planning the retrieval and transfer procedures, intended parents should discuss the action plan with the surrogacy agencies and the donation clinics. It is important to know how they plan the cycles, whether or not they give the opportunity to freeze embryos, which methods they use and how they come in accordance to the best practices of the embryo transfer .