Frequently asked questions
How does a PGD cycle differ from an IVF cycle?
A PGD cycle involves taking a few cells off an embryo when it has developed to the blastocyst stage and is typically made up of 100 to 120 cells. This small piece is then analysed for specific gene problems or for chromosome numbers. The best embryo that contains no identified genetic problem would then be transferred. In IVF, the best looking embryo is the one transferred - no further information is available in making this choice.
Is the sex of the embryo part of the test?
CGH does identify the sex of an embryo. The sex chromosomes are an important source of miscarriage, and aneuploidy involving these chromosomes can result in children with syndromes. Genea does not however, use this information for social sex selection reasons.
What does the 95% accuracy really mean?
Nothing is 100% guaranteed and so for various biological and technical reasons, Genea will only give 95% as a confidence value. This does not necessarily reflect a 5% risk of a chromosomal imbalance in the embryo but it is there to reflect a level of uncertainty associated with testing at such an early stage of development. Such testing cannot account for all problems in a foetus as it develops. Each couple will have their own imperatives as far as follow up testing of any ensuing pregnancy.
Is there any difference in fertilization rates between IVF and ICSI?
The fertilisation rates are similar and range at approximately 70% of mature eggs. Fertilization is indicated by an equal contribution from both egg and sperm and is seen in the laboratory as the presence of two pronuclei approximately 18 hours after the sperm and the egg are combined.
Is ICSI known to cause birth defects?
To date there have been no conclusive studies indicating that ICSI induces birth defects. The outcomes from all assisted reproductive technologies continue to be monitored by various governmental and professional groups around the globe. In Australia the outcomes are collated by ANZARD. This is released yearly; however the data is delayed by 2 years due to collection and analysis requirements. Genea contributes all of our data to this group.
Does IVF/PGD cause an increase in birth defects and abnormalities?
In order to access PGD services couples are required to undergo an IVF cycle. As mentioned above, there is no link established to birth defects and the use of IVF/ICSI combined with PGD.
Does assisted hatching hurt the embryo?
The use of ear infra red lasers has been common place in IVF or PGD since 1996. The use of these lasers has improved the outcomes following PGD analysis. Consequently the use of the laser has proved beneficial to the process and is not known to be bad for human embryos. Used in an incorrect manner the laser could do harm to the embryo and for this reason training protocols and ongoing quality controls are in place; as is the case with all procedures conducted at Genea.
How do you grade embryos and what does that mean?
At Genea embryos are generally graded on using their development stage (e.g. 8-cell, blastocyst, etc.), level of fragmentation, specific criteria for each stage and a grading system of 1, 2 or 3 which takes into account all of the above. Generally 1 or 2 on Day 5 or 6 is suitable for transfer or vitrification, while 3 is considered unsuitable. However if a patient has only Grade 3 embryos and wishes them to be transferred we will do so albeit the pregnancy rate is significantly lower than for Grades 1 or 2. Biopsy requires an assessment in addition to normal grading. This assessment is based the blastocyst hatching and having sufficient trophectoderm to biopsy.
What will happen to all my other embryos which did not become suitable?
If you have not consented to investigation they will be discarded. If you have consented then they will be documented and may be used in some investigative procedures. Under international guidelines affected or abnormal PGD embryos may be re-biopsied for confirmation of results.
How can we avoid having multiple pregnancies, twins, triplets etc.?
Genea clinicians generally adhere to a strict single embryo transfer policy in order to avoid any complications arising from multiple pregnancies (such as twins, triplets, etc.) When circumstances deem it appropriate then two embryos are transferred; however this is not a regular occurrence.
Do you recommend that we do prenatal screening?
PGD recommends that prenatal testing is discussed with your clinician at the appropriate time as you would in any pregnancy. However, it is the patient’s decision and must be made based on a number of factors and following discussions with their clinician.
How long are our DNA stored for?
DNA samples are stored indefinitely. However any person whose DNA sample is stored at Genea may notify us in writing and have their sample disposed off. No DNA sample will be used for anything other than establishing and using the specific test for the specific couple it was collected on behalf of without first obtaining the expressed permission of the DNA's owner.
Do you biopsy all embryos that become suitable even if they develop at different rates?
Embryos are assessed for their suitability for biopsy at multiple stages on the morning of Day 5 then again in the afternoon and then on the morning of Day 6. All embryos which become suitable for biopsy (even if you have already had a transfer) will be biopsied and analysed.
Should we go ahead with the biopsy if we only get one embryo suitable for the procedure?
Aneuploidy screening is applied in a PGD setting in order to allow for an additional selection criterion (based on embryo genetics) to the current standard IVF morphological grading processes. The main aim of PGD in this setting is to apply the additional information gained through the testing in order to help choose the best embryo for transfer within a cohort available for selection (i.e. when there are a number of good embryos to choose from). Patients in this category include those which present with advanced maternal age, a history of recurrent miscarriage or recurrent implantation failure.
In a situation where there is only a single embryo available on Day 5, the need for applying further selection criterion in the form of a genetic screen should be closely re-evaluated (this should be discussed further with both the PGD scientists and your doctor). If you are presenting for aneuploidy screening then selecting against embryos which show chromosomal abnormalities may improve your chances of achieving a viable pregnancy. However the tests which we apply are not 100% accurate. We provide a reliability of 95% for a 'normal'. These tests may also give false 'abnormals' which means that we may lose good quality embryos to poor test performance. Choosing to transfer your best embryo directly without any further manipulation may be the best choice under the circumstances and should be discussed with your clinician.
If you are presenting for translocation testing you have the option of transferring the embryo directly without testing with on the understanding that you return at the untested risk for an abnormality in any resulting pregnancy. In these situations Genea recommends you discuss any concerns with your clinician and that you also consider prenatal testing.
Do all embryos survive biopsy?
Embryos which are of good quality (that is Grade 2 and above) have a greater than 99% chance of surviving biopsy. In some cases (such as patients whose embryos have a high risk of abnormality due to single gene defects or translocations, etc) when an embryo is available for testing but the embryo is just outside of our standard criteria for biopsy, patients may choose to attempt a biopsy rather than miss an opportunity for transfer. If they do not wish to transfer the embryo without PGD testing then in such cases the risk of not surviving is higher. Decisions under these circumstances are ultimately made by the patient.
Is biopsy detrimental to the embryo?
Our experience shows that in our hands embryo survival following a blastocyst biopsy procedure is close to 100%. Furthermore we only biopsy from the trophectoderm; the tissue which contributes towards the placenta. We do not biopsy the inner cell mass; the part of the blastocyst from which the foetus is ultimately formed. There is no evidence at this point to suggest that the procedure induces abnormality in the embryo. Data available suggests that there is no significant difference between IVF and PGD babies in terms of congenital birth defects.
If we have a biopsy when will my embryo transfer be? How am I informed?
At all stages a PGD Nurse Co-ordinator will keep you informed of the progress of the embryos. This includes whether any embryos were biopsied, the number biopsied, and the approximate time results will be available. If there is a suitable embryo the Nurse will arrange a transfer time with you. A PGD scientist will discuss the results, etc. at the transfer.
Can we put back an embryo that has been found to be abnormal or affected if it is the only embryo we have?
Genea will not knowingly transfer an embryo which has been detected to be abnormal through any PGD testing process. If this is an issue which concerns you then please discuss this further with your clinical geneticist and treating IVF specialist as soon as possible before the commencement of treatment.
If none of our embryos become suitable for biopsy, or all of the tested embryos are abnormal, can we put back the best embryo untested? What are the risks if I do?
If no embryos meet our criteria for testing, or if all of the tested embryos are abnormal, there may still be some embryos which qualify for direct transfer untested. Patients may choose to transfer these with the understanding that they are back at their age specific population risk for any chromosomal errors and/or their direct risk of an abnormality due to a single gene disorders or translocation. This risk can be anywhere from 25 to 50% for single gene disorders and possibly higher for balanced translocation carriers and aneuploidy.
Is there a possibility that my test may not work properly on the day? How will this be handled by the laboratory?
We achieve results in greater than 95% of embryos biopsied. However there are a number of factors which may lead to 'no diagnosis'. The biopsied tissue sample is very small and undergoes several manual handling steps during which there is potential for loss. Additionally there are a number of factors that can lead a test to a 'fail' on the day. There may be other factors that lead to an incomplete test for a particular sample. This may lead to a lowered reliability rate. All results would be discussed with the patient.
However for most embryos results will be reported at the reliability at which the test was offered.