While it is the dream of every In Vitro Fertilization (IVF) practitioners to see their patients get pregnant after every cycle, fertility experts have said maternal age and viable embryo, are still the main factors that could make or mar IVF success rate.
Fertility experts, at a webiner with the theme: “Optimizing IVF Success in the ART Laboratory”, organized by Nordica Fertility Centre and the Association for Fertility and Reproductive Health (AFRH), said while contribution to implantation from an embryo is about 60 per cent, live birth per embryo transferred for all IVF patients increases with patients aged under 43.
The managing director, Nordica Fertility Clinic, Dr. Abayomi Ajayi said if wishes were horses, IVF practitioners would want all their patients to get pregnant after every IVF cycle. “However we know that this is far from what the technology delivers presently,” he added.
Ajayi, while quoting data from the 2018 Human Fertilisation and Embryology Authority in the UK, said there is an average birth rate of 23 per cent per embryo transferred, and these rates have steadily increased over time for all patients under the age of 43. “We know that implantation continues to be the main limiting factor in IVF success and for us to have implantation, there must be a viable embryo,” he said.
In the same vein, Clinical Embryologist, Nordica Fertility Centre, Joy Ehichioya said, in assisted reproduction, Embryologists are constantly taking and making decisions at every stage of the process and one crucial decision to take is embryo transfer, which is also a stage in IVF process, where the Embryologists decide on what day they want to transfer the embryo, how many embryos they want to transfer and select for transfer.
Ehichioya said Assisted Reproductive Techniques have made many advancement since 1978 and various approaches have been undertaken including those that assess embryos either sequentially at several stages of development or only once, immediately before transfer, and in a bid to increase pregnancy rate, about two to three embryos are usually considered for transfer, with the goal of at least one implanting leading to live birth.
On how to know the best embryos to select, the Embryologist said, “We have selection based on the morphology, that is how the embryos look, how they appear under the microscope. Studies have also listed metabolomics, to be part of the selection tools. This allows us to measure the profile of different key components in embryos culture media, but its efficacy is still under debate.
“There is also pre-implantation genetic testing, which is also done prior to embryo transfer, and it helps to clarify the issue of genetic well-being of embryos, but this is not a standard practice in many IVF clinics across the world because there is an additional cost that is attached to this kind of service.
“Time lapse imaging which is simply an advance stake on a standard morphological analysis which provides more frequent observation in a controlled environment, is also a tool used in the selection of embryo. In this case, the frequent observation is believed to provide substantially more information about the relationship between timing and embryo viability.
“The next tool is artificial intelligence which is new right now. This is roughly modeled after the neural networks of the brain, which analyze information in increasing layers of complexity. With this new technique, the IVF procedure still remain the same, but it helps to improve outcomes.
Speaking on the stages of assessment of the embryo, while there are Cummulus Oocyte Complex stage, Pronuclei stage, Cleavage stage and Blastocyst stage, Ehichioya said emphasis is placed on the Cleavage and Blastocyst stages.
She said minimal requirements for embryo selection should include standardisation, ease of assessment, objectivity, minimal harm to embryo and a high correlation with pregnancy rates.
Outside transferring a good embryos, the Embryologist said age also play an important role, adding that studies have shown that day five embryo transfer for women less than 35 years have a success rate of more than 50 per cent and then dropped to 3.2 per cent for women above 44 years old.
Baring all of these in mind, she said active research is needed in developing more non-invasive methods for scoring embryos and ranking them according to their ability to implant and give rise to a healthy birth.