What is Embryo Genetic Diagnosis (PGT or PGD)?
Rapid developments in medical technology enable us to identify and produce solutions for many problems that we have had difficulty explaining until today. One of the best examples in this regard is the possibility of "genetic diagnosis in the embryo", which allows the health of the pregnancy to be determined before pregnancy occurs. It is possible to examine the baby's health while it is still at the 7-8 cell embryo stage. In this way, the placement of a sick or genetically defective embryo in the uterus and the formation of an unhealthy pregnancy are prevented from the beginning.
Who Can Perform Embryo Genetic Diagnosis (PGT or PGD)?
In order to perform genetic diagnosis (PGT or PGD) on embryos, these embryos must be developed under laboratory conditions. For this, the egg cell obtained from the woman and the sperm cell obtained from the man must be brought together in a laboratory environment, that is, fertilization and embryo development must be achieved through in vitro fertilization or microinjection techniques. In other words, genetic diagnosis in embryos requires a laborious and costly high-technology application. Therefore, this technique is only applied to couples with special risks. For which couples Embryo Genetic Diagnosis (PGT or PGD) will be applied varies depending on the purpose of the application.
Embryo Genetic Diagnosis (PGT or PGD) can be performed for different purposes:
1. Anomaly screening
2. Disease investigation in embryos
3. Identification of cancer and disease in risky families
Anomaly screening
Those who have difficulty in having children and in couples with an increased risk of anomaly in the embryos obtained during treatment, it is aimed to screen the embryos for the most common chromosomal defects.
The aim of anomaly screening is to aim for the most common trisomy (more than normal number of chromosomes) or monosomy (chromosomal abnormalities) in embryos. It is the determination of chromosomal anomalies such as the number of chromosomes being less than normal). Embryos found to have abnormalities are not transferred into the uterus and are destroyed. Only embryos known to be healthy are transferred to the patient. In this way, a baby with a genetic anomaly The risk of embryos developing inside the uterus is eliminated from the beginning.
Usually, embryos with genetic anomalies cannot survive in the uterus. Even if retention occurs, pregnancy often ends in miscarriage within the first 10 weeks. In fact, this situation creates a great advantage for human nature to maintain its own balance. Nature tries to eliminate the unhealthy while preserving the healthy. In this way, we see very few babies or children with anomalies around us. However, unfortunately, this rule is not always valid.
If the embryo carries severe genetic defects, it is usually distinguished from others during observation in the laboratory due to its slow development, stalled development or poor quality development, and such embryos are not placed in the uterus. However, the development of embryos carrying simple trisomy (Down Syndrome; trisomy 21) or monosomy can be as good and fast as healthy ones. It is impossible to distinguish these embryos from others by their development speed, appearance and quality. Embryos carrying such anomalies can attach to the uterus and cause babies with anomalies to be born. Although the majority of babies with anomalies abort in the early period, a significant portion of them may survive until later weeks of pregnancy. Such problems are detected by ultrasonography, blood tests and, if necessary, amniocentesis methods during careful and regular pregnancy follow-up. As the pregnancy progresses, learning that the baby has an anomaly and terminating the pregnancy is extremely traumatic. It should not be forgotten that if pregnancy follow-up is not carried out at all, the birth of a disabled or disabled baby is possible.
Assisted reproductive techniques are performed for some couples who have difficulty in having a child. In this technique, embryos are obtained by microinjection method using sperm and egg cells belonging to the couple. If the couple has a high risk of genetic anomalies in the embryos, Embryo Genetic Diagnosis (PGT or PGD) is recommended. Couples at high risk can be listed as follows:
-Recurrent early pregnancy losses (miscarriages)
-A previous history of anomaly birth and miscarriage
-Some special morphological anomalies of the egg or sperm cell
-A The age of the expectant mother is 37 and over. - Failure to achieve pregnancy after repeated in vitro fertilization - microinjection treatments or the pregnancies that have been achieved have ended in miscarriages. does not recommend doing so. In this regard, the CCS method, which has recently come into routine use, can be recommended.
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