Which is the best embryo to transfer? To improve the efficiency of IVF treatments it is essential to identify the right embryo, the one that will lead to a healthy child at home.
Unfortunately, even the transfer of a morphologically “perfect” and chromosomally assessed embryo, does not guarantee a pregnancy.
New methods for the identification of viable embryos are urgently required. It is clear that many other elements play a key role in embryo viability. One of this elements seems to be mitochondrial DNA, which has been one of the main issues in past ESHRE 2016.
Mitochondria are intracellular structures that can be seen as “source” or “processors” of energy. Although DNA is mostly packaged in chromosomes within the nucleus of the cells, mitochondria also have a small amount of their own DNA (“extranuclear” DNA).
Scientists are not sure why some embryos experience a sudden rise in mitochondrial DNA but according to many studies presented at last ESHRE congress, those morphologically and chromosomally “perfect” embryos with unusually high levels of mitochondrial DNA have no ability to produce a baby. One possibility is that defective embryos make more mitochondria to give them enough energy to survive, but ultimately fail to develop and stop growing.
Taking this into account, mitochondrial quantification seems to be a “new” good candidate to be used as a marker of embryo viability in those chromosomally normal embryos.
We do know that thanks to assisted reproduction a pregnancy will be achieved in most cases. However, many times, the road is long and tortuous. And, as a consequence, many patients cannot withstand such a long way and decide to discontinue treatments before conceiving. The question we should be able to answer is why some couples discontinue their treatments.
Research focusing on treatment’s dropouts has been performed. Both physical and psychological burden are the most mentioned causes of treatment discontinuation. Reduction the time to birth (i.e. the period of time from the initial visit to an assisted reproduction center and the achievement of a pregnancy) implies many issues. First, the diagnostic work-up should be simplified avoiding useless diagnostic tests. Second, nowadays, we may propose more comfortable and safer ovarian stimulation strategies (using GnRH antagonists instead agonists or by administering single doses products) thus shortening the treatment, reducing injections and avoiding ovarian hyperstimulation syndromes. Third, laboratory procedures allow us to select the embryo with the highest chance of implantation (incubating embryos into video-time- lapse systems, selecting genetically the embryo, transferring on day 5, avoiding multiple pregnancies).
But even with these advances, many cycles result in failed attempts. In such cases, treatment burden should be reduced by better care organization and support for patients. At this point patients should be well informed, have the opportunity to discuss values and worries about treatment and receive advice to decide whether to continue or not treatment.
This support (information of previous failed attempts, proposal of new treatments and discussion worries) is of utmost importance for patients.
María De Las Heras from Reproducción Bilbao performed a [wp_colorbox_media url=»https://reproduccionbilbao.es/wp-content/uploads/2016/06/ESHRE2016.-POSTER-Reproduccion-Bilbao.jpg» type=»image» hyperlink=»poster presentation«] at 32 nd ESHRE Meeting at Helsinki. The validation of the Eeva testTM algorithm in an Embryoscore incubator was assessed.
The published data confirmed a positive and significant association between the high scored embryo transfers and a higher ongoing pregnancy rates.
The advantages of undisturbed embryo culture in a stable device such as the EmbryoScope time-lapse incubator in association with the use of the model of Eeva Test TM do represent an important improvement in IVF, reducing early pregnancy loss and increasing ongoing pregnancy and implantation rates.
Moreover, although the evaluation of morphokinetics of embryos does not replace the genetic embryo selection, it is hard to understand how standard incubators without any kind of video-time- lapse system are still in use in some assisted reproduction centers. In this setting, the ability to choose the most suitable embryo to be transferred allows to perform a single embryo transfer in most of the cycles at Reproducción Bilbao, thus avoiding multiple pregnancies.
Joaquin Llacer from Instituto Bernabeu (Alicante) offered one of the most brilliant and awesome presentations at ESHRE Meeting held at Helsinki this month. It is admitted that embryo aneuploidy frequency increases with women’s age. According to data from Instituto Bernabeu as much as 40,6% of analyzed embryos showed some type of aneuploidy. Overall, this means that the fate of 4 out of 10 embryos will be either no implantation or a miscarriage. As expected, the aneuploidy rate increased with age. The rate was higher than 80% among women aged 42 and older. No news, here.
But the relevance of Joaquin Llacer`s presentation was the high and in someway surprising high rate of aneuploidies observed among women younger than 22. More than 40% of embryos from women included in this young range were faulty from a chromosomal point of view. This means that even in an egg donation program it is worthwhile to analyze the embryos to be transferred.
In summary, two lessons may be learned from this outstanding presentation. First, the transfer of embryos without a chromosomal analysis (i.e. without performing a genetic screening) will (should) be reduced in the future taking into account that as much as 4 out of 10 embryos may be defective (so, 6 out of 10 useless embryo transfers could be avoided). Second, and more surprisingly, even in the context of an egg donation program genetic screening may be suitable. Anyway, if an egg donation treatment is proposed, it is advisable to choose donors older than 21.
