Spare embryos & embryo research
After an IVF attempt there is a possibility that some embryos remain. If the number of eggs fertilized is high, we do not transfer all the embryos to eliminate the risk of multiple pregnancies. Research has shown that increasing the number of embryos transferred does not increase pregnancy rate but only the increase of twins etc.
In these cases there remain surplus embryos (spare).
The Importance of consent forms
Greece is one of the last counties in Europe that legislation has been imposed.
A consent form is a necessary part of the IVF unit practice and concerns your rights and the rights of the IVF center.
Embryo Quality and Freezing
Freezing may be one of the options available if there are supernumery embryos.
While freezing embryos may increase the overall success per egg collection (cumulative percentage- with fresh and frozen embryos) the success relies heavily on the number and suitability of embryos. Only the embryos with good morphology survive the freeze/thawing technique.
You should be aware that a consent form might often be requested for the length of storage and the fate of the embryos in the event of divorce etc.
What is a good quality embryo?
Because we have differences in oocyte quality, it is logical to presume that not all the embryos will be the same quality. In an attempt to choose the best quality of embryos to be transferred, the embryologist will use a grading system to score the embryos based on embryo development and morphology.
The grading system will help the IVF team decide how many embryos should be transferred and deduce the possibility of freeze/thaw success of the “spare embryos”.
The score can give an overall picture of the IVF treatment cycle and help decide on any future protocol changes if needs be.
It more objective to inform the clinician on the grade of embryos rather than to say that they are “nice”!
The scoring system is used by Hammersmith Hospital, London and Mitera Maternity Hospital, Athens.
The embryo scoring system is from 1(best)to 5 (worst).
Research and its importance
The word research may be misleading and tends to lead the mind to thoughts of science fiction.
Most research in this field aims at improving IVF Success rates. This may be as simple as investigating the nutritional needs of an embryo and trying to produce a culture medium more like its natural environment.
Another form of embryo research is investigating ways of choosing the best embryos by criteria other than morphological assessment.
The advances in genetics have helped us learn more about the developing embryo and techniques are available to choose embryos free from certain genetics inherited disorders.
Spare embryos are given for research after the written consent is given. The embryos donated are the ones left after the embryo transfer. It is forbidden in most countries to generate embryos solely for research. The embryos are naturally of poorer quality (the best having been transferred or frozen) and can no longer be used in the fertility treatment.
