Scientists discuss how the latest reproductive technological advancements like PGDPreimplantation Genetic Diagnosis (PGD) and Preimplantation Genetic Screening (PGS) are contributing to better IVF success rates. Dr Khajuria completed her Ph.D from AIIMS, New Delhi in the field of Molecular Genetics from the Department of Pediatrics. While working in AIIMS for 9.5 years she was involved in research and diagnostics of various pediatric genetic disorders. An edited excerpt:

On the role of genetics in infertility

Reproductive genetic risk and infertility has become a global problem and is increasing with time due to different factors including our changing life styles and environmental factors. This has led to an increased demand for assisted reproductive technologies (ART) and genetic services. It is now known that the cause of infertility may also be of genetic in origin, and delayed motherhood increases the risk of embryonic chromosomal abnormalities.

Family history of genetic disorder affecting the new born

If a couple has a family history of recessive genetic disorder, the risk of passing the same to the newborn is 25%. If the couple has a family history of diseases and disorders, in that case it is recommended to plan a healthy future for your baby by opting the service of PGD (Preimplantation genetic diagnosis) and PGS (Preimplantation Genetic Screening).

Now this is known that every human contains 3-5 recessive genes in them and if their partner carries the same recessive gene, the chances of their baby being affected are more. So, it is important for such couples to get themselves tested before planning their pregnancy so that they can avoid this risk of passing on the genetic disorders to their to be born child.

On technological advancements introduced in IVF

Initially, IVF was used to treat women with blocked, damaged, or absent fallopian tubes. Today, IVF is used to treat many causes of infertility, such as endometriosis, male factor, and in unexplained cases of infertility. Today with the inclusion of many new genetic technologies, IVF success rate has been increased.

Recent technological advances in the reproductive medicine field have made genetic carrier screening test affordable for everyone. These tests provide the screening of hundreds of recessive genetic disorders simultaneously and these tests can be offered to those patients too who do not have any family history of a genetic disorder, therefore they can be used at pre-conception level. Finally, in those cases in which this test shows an increased risk of having a genetically abnormal offspring for any of the tested conditions, PGD can be offered to these couples to avoid the birth of affected offspring for the tested condition.

PGD was first used to discard affected embryos in carriers of single-gene disorders and with evolution in techniques; PGD is also used to discard embryos having structural chromosome anomalies in couples having known abnormal karyotype. There is another form of PGD which is applied to the screening of numerical chromosome anomalies in couples with normal karyotype, but with infertility problems and is termed as PGS.

PGS is offered in many IVF centres to improve IVF outcome of certain groups of patients. Current clinical indications for PGS are: advanced maternal age, recurrent miscarriage, repetitive implantation failure, and severe male factor infertility. PGD & PGS came into existence in India only 4 years back and have been largely used and recommended by specialists looking at the benefits associated with them. Employing PGD + PGS together ensures pregnancy success rate of 42.9%

This is important to note that PGS and PGD only rules out that your embryo is healthy and free of the disease, aneuploidy or structural rearrangement but the successful implantation of the embryo in uterus also requires a receptive endometrium. Endometrial receptivity was rarely investigated in an infertile patient. Endometrial Receptivity Analysis (ERA) is another advancement of modern technology which determines the correct window of implantation, increasing the chances of successful IVF by personalizing embryo transfer.

On the challenges and risks involved with new evolving technologies

Modern ART associated with genetic screening is becoming a new era of infertility treatments for couples providing a chance of healthy pregnancy within one IVF cycle. As this field is evolving very fast, there is a need of having a multidisciplinary approach including clinical geneticists, IVF consultants, embryologist, genetic counselors and the patients, so that a proper diagnosis and counseling can be given to the family to make better decisions.

As the new reproductive technologies are being introduced, this also brings the need to validate all these new techniques based on preclinical and clinical research evidence for their efficacy, cost effectiveness and long term benefits before implementing them in clinical setting.


Source: health economic times