In vitro fertilization (IVF) has led assisted reproductive technologies for almost 40 years (ART). IVF has been utilized to get around some of the most prevalent reasons for infertility, like abnormal sperm in men and damaged fallopian tubes in women.
IVF technology advancements have provided fertility specialists with a new tool to help their patients. In the United States, many fertility clinics now provide pre-implantation genetic screening (PGS).
When scanning embryos with PGS, fertility professionals utilize specialized technology to check for an improper number of chromosomes (main carriers of human genetic material). (1)
What is the Screening Embryo Test?
An embryo at day five contains roughly a hundred cells. Through a special biopsy, the embryologist can remove up to five cells for analysis without damaging the embryo.
“On day five of embryo development, we take some cells from the outside of the embryo,” says Mark P. Trolice, board-certified reproductive endocrinology and infertility specialist and founder of the IVF Center. “That tissue is used for genetic analysis. While we wait for the results, we freeze the embryos in the meanwhile.”
Dr. Trolice has witnessed some remarkable advances in embryo screening over the years. “We can test for chromosomal abnormalities like embryo sex, Down Syndrome,” he says. “This is very important for an old woman doing IVF; We can also screen for single gene defects such as sickle cell anemia, cystic fibrosis, Tay-Sachs.”
Screening embryos can help fertility specialists guide IVF embryos with the highest potential and probability of producing a viable pregnancy.
“All of this allows a woman and couples to reduce their worries about problems with their baby before they get pregnant,” says Trolice.(2)
Is it possible to avoid Down syndrome with IVF according to fertility experts?
According to Raúl Olivares Gynaecologist, Medical Director & Owner Barcelona IVF
Yes, if you do PGS on the embryos, you can find trisomy 21 or Down syndrome. There are three different PGS. One of them checks the accuracy of the chromosomal number. Additionally, you can look for mutations within the chromosomes or determine if there has been a translocation or a change in the arrangement of the chromosomes.
Since we find aneuploidies, which are anomalies in which the embryo has extra chromosomes or is missing a chromosome, the first of these three is the so-called PGT-A. Embryos are said to be triploid if they have one extra chromosome.
It is known as monosomy if there is only one chromosome in the embryo, and all of these problems are either redundant or may be discovered by PGS because there is no chromosome present in the embryo.
According to Glykeria Samolada (Geneticist, EuR Genetic Counsellor)
It is necessary for high-risk situations and pregnancies brought on by older mothers or chromosomal rearrangements involving chromosome 21 to use pre-implantation genetic testing in IVF to completely eliminate the danger of down syndrome with three copies of chromosome 21.
Utilizing the pre-implantation genetic testing technique is quite beneficial in these circumstances. In any case, it’s critical to remember that pregnancy during the prenatal testing process needs to be taken into account and monitored the same as any other pregnancy.
According to Luca Gianaroli (Gynaecologist, Scientific Director S.I.S.Me.R.)
I cannot say that you can prevent Down syndrome 100% with IVF. Although there is still a small chance of misdiagnosis, it can lower the possibility of having a child with Down syndrome.
A 40-year-old person’s risk of being pregnant with Down syndrome, whether spontaneously or through IVF, is 2.5%. Pre-implantation genetic testing allows you to reduce this 2.5% risk by 98%. It reduces the risk to an individual or couple to a minimum.(3)
To sum up
Studies have shown that chromosomal abnormalities present in about half of all IVF preimplantation embryos can result in implantation failure and miscarriage in the first trimester of pregnancy. The quality of a woman’s eggs declines with age, and the chance of an embryo with genetic defects rises.
Women and couples can avoid these issues before they arise by having embryos screened for both chromosomal abnormalities and genetic flaws.
Is IVF itself a risk factor for Down syndrome?
Contrary to common misconceptions, IVF does not inherently lead to Down Syndrome. This genetic condition stems from an atypical cell division, producing an extra chromosome 21. Such an occurrence is spontaneous, indifferent to the method of conception. Nonetheless, an indirect relationship exists, primarily due to maternal age. Older women, who more frequently opt for IVF, face an elevated risk of birthing a child with Down Syndrome.
Key points to consider include:
- The abnormal cell division related to Down Syndrome is independent of the IVF process.
- The age factor significantly correlates with the probability of Down Syndrome, impacting older mothers more.
- Pre-implantation genetic screening within IVF serves as a pivotal tool. It screens for chromosomal irregularities, thus enabling the selection of embryos least likely to carry Down Syndrome.
Given this context, IVF’s association with Down Syndrome primarily hinges on the age of the woman undergoing treatment. Despite the absence of a direct causative link, the age-related risk remains relevant. Advancements in genetic screening within IVF protocols offer a pathway to mitigate this risk, albeit not entirely eradicating it. Therefore, seeking guidance from a genetic counselor becomes essential for prospective parents to navigate these complex considerations effectively.
Source:
Maymon, R., & Shulman, A. (2004). Integrated first‐and second‐trimester Down syndrome screening test among unaffected IVF pregnancies. Prenatal Diagnosis: Published in Affiliation With the International Society for Prenatal Diagnosis, 24(2), 125-129.
