The advantages of comprehensive chromosome screening (PGS/PGT-A/CCS) in women of an advanced maternal age

Women currently seek guidance on reproduction at a much older age than they did some years ago. As a result, amongst the women who undergo fertility treatment, there is a significant group of women of an advanced age and their prognosis is poorer. This is a huge challenge for reproduction specialists.

Age has a negative impact on all aspects of fertility in women, but particularly on the quantity and quality of oocytes. A woman’s ovarian reserve decreases from 35 years of age and this decrease is significant when she reaches 38 or 40. It not only affects the quantity of oocytes, but also their quality. It has been proven that chromosome abnormalities in the oocyte increase with age and that they are then passed on to the embryo. This leads to embryos with a poorer ability to implant or that lead to pregnancy loss or children with malformations.

Therefore, when a woman aged over 38 or 40 undergoes assisted reproduction treatment using her own oocytes, it is important to select the very best strategy for guaranteeing excellent results. On the one hand, this means selecting the stimulation protocol that will generate the largest quantity of oocytes. On the other, it is a matter of ensuring that the embryo that is transferred is the one with the greatest chance of implanting and giving rise to the birth of a healthy child. As well as selecting the embryo with the best morphology, this can be achieved by carrying out comprehensive chromosome screening (CCS or PGS) thanks to the advanced technology such as array CGH or next-generation sequencing (NGS) that is currently available. Recent research at Instituto Bernabeu has demonstrated the advantages of using these techniques for embryo selection in women of an advanced maternal age. When this technique was used, the same implantation rate was achieved in women of an advanced age compared with young women following selection of chromosomally normal embryos (euploid embryos). These results are backed up by a worldwide scale randomised clinical trial (The STAR Trial-Illimina) performed on a large number of patients. The research shows, therefore, that PGS/CCS/PGT-A is a promising option for improving the results of cycles of in vitro fertilisation (IVF), particularly in patients of an advanced maternal age.

Dr Ruth Morales, molecular biologist at Instituto Bernabeu