Can IVF avoid birth defects?
Birth defects are a major concern for many prospective parents during the process of preparing for and giving birth to a child. With the development of IVF technology, many people expect to reduce the risk of birth defects through this assisted reproductive technology. So, can IVF really avoid birth defects?
I. Advantages of IVF technology in reducing birth defects
1. The core of the third generation of IVF – Pre-implantation Genetic Testing (PGT) technology
This is an important tool used in IVF to screen the genetic material of embryos. PGT technology includes PGT – A (Aneuploidy Screening), PGT – M (Monogenic Disease Detection) and PGT – SR (Chromosomal Rearrangement Detection).
PGT – A: It is mainly used to test whether the chromosome number of the embryo is normal. During natural conception, chromosomal abnormalities in embryos are an important cause of early miscarriage and birth defects. With PGT-A, all 23 pairs of chromosomes in an embryo can be screened and those with a normal number of chromosomes can be selected for transfer. For example, as the quality of eggs of women of advanced maternal age decreases and the probability of chromosomal abnormalities in embryos is higher, PGT – A technology can effectively reduce birth defects such as Down’s Syndrome caused by abnormal chromosome numbers.
PGT – M: For known single-gene genetic diseases, such as thalassaemia and cystic fibrosis. If both husband and wife carry the causative gene of a certain single-gene genetic disease, PGT – M can detect whether they carry the causative gene at the embryo stage, so that healthy embryos without the causative gene can be selected for implantation, thus fundamentally avoiding the emergence of this type of single-gene genetic disease in the offspring.
PGT – SR: It is used to detect the presence of chromosomal structural abnormalities, such as chromosomal balanced translocations and inversions. These chromosomal structural abnormalities may lead to abnormal embryonic development or birth defects. With PGT-SR, embryos with normal chromosome structure can be screened out, reducing the risk of birth defects caused by chromosome structure problems.
2. Optimised culture environment and early embryo monitoring
During IVF, embryos are developed in a petri dish in the laboratory for a period of time. A state-of-the-art reproductive medicine centre will provide the embryos with culture conditions that are as close as possible to the human intrauterine environment, including the right temperature, humidity, gas concentration and nutrients. At the same time, laboratory staff will closely monitor the early development of the embryo, such as the rate of cell division and morphology of the embryo. Such fine monitoring can help screen out embryos with better developmental potential, which are relatively less likely to have problems during subsequent development, and also reduce the risk of birth defects to a certain extent.
II. Reasons why birth defects cannot be completely avoided
1. Limitations of the technology
Although PGT technology is capable of detecting many kinds of genetic defects, it still has certain limitations. For example, PGT technology cannot detect all genetic defects, and there are many complex polygenic genetic diseases whose pathogenesis involves multiple genes as well as gene-environment interactions, and it is still difficult for current technology to accurately screen embryos for these conditions. Some birth defects like congenital heart disease and neural tube defects may be affected by a combination of multiple genes and environmental factors during pregnancy, and IVF techniques still face challenges in preventing these defects.
2. Influence of extra-embryonic factors
Apart from the genetic factors of the embryo itself, there are many extra-embryonic factors that may cause birth defects. During the course of pregnancy after a successful IVF transfer, the lifestyle of the pregnant woman, environmental factors, and infections may all have an impact on the development of the foetus. For example, infection of pregnant women with pathogens such as rubella virus and cytomegalovirus during pregnancy may lead to birth defects such as congenital deafness and mental retardation in the foetus; pregnant women who are exposed to harmful chemicals (e.g. formaldehyde, benzene, etc.) or radiation for a long period of time may also increase the risk of birth defects in the foetus.
3. The role of epigenetic factors
Epigenetic refers to a modulation of gene expression that occurs in a heritable manner without changing the DNA sequence. During embryonic development, epigenetic factors such as DNA methylation and histone modification affect gene expression. Certain manipulations during IVF, such as in vitro culture, freezing – thawing, etc., may have certain effects on the epigenetic status of the embryo. Although there is no clear evidence that these effects can directly cause birth defects, this potential factor also indicates that IVF technology cannot completely eliminate the risk of birth defects.
III. Case Sharing
1. Genetic Disease Prevention Cases
There is a couple, both of whom are carriers of the thalassaemia gene. They have gone through the painful process of multiple failed natural conception or termination of pregnancy due to the fear of foetal disease. Later, they chose the third generation IVF technique. Through the PGT-M test, the doctors screened for healthy embryos that did not carry the thalassaemia gene at the embryo stage for transfer. Eventually, his wife successfully got pregnant and gave birth to a healthy baby, completely getting rid of the shadow of Thalassaemia inherited in the family.
2. Chromosomal Abnormalities Prevention Case
A woman of advanced maternal age had a high risk of chromosomal abnormality in her embryo after pregnancy. During the third generation IVF, the embryos were screened by PGT-A technology and those with abnormal chromosome number were excluded. After the transfer of normal embryos, she was successfully pregnant. The pregnancy went smoothly and the baby was born very healthy with normal indicators.
With its advanced pre-implantation genetic testing technology, IVF provides the most direct and effective solution to prevent birth defects. Although there are still some limitations, it has a promising future and has already brought the gospel of having healthy babies to many families. It is hoped that as the technology continues to advance, it will benefit more families, so that every new life can begin a beautiful journey of life on a healthy starting point!