IVF Unica - Institute of Reproductive Medicine, oocytes, Oocyte Donation, Donated eggs, IVF, Brno, Czech republic
IVF Unica - Institute of Reproductive Medicine, oocytes, Oocyte Donation, Donated eggs, IVF, Brno, Czech republic
The basic therapeutic method is called in vitro fertilization (IVF). The popular expression is “artificial fertilization” or “test-tube fertilization”, because the connection of the sperm with the egg happens in a laboratory, outside of the woman’s body.
During IVF, sperms are added to the retrieved eggs in a special plate and special media, but they have to penetrate the individual eggs by themselves. In case of men with normal sperm, the so-called normospermics, approx. 50% of retrieved eggs get fertilized in this way, i.e. even with normospermics, a quality sperm does not fertilize each egg.
The quality of sperm that penetrates into an egg during IVF is unknown. It remains a matter of coincidence.
Unfortunately, an abnormal spermatozoon may also penetrate the egg and fertilize it. An embryo may develop even from such an abnormal sperm and the woman may get pregnant with such abnormal embryo. However, in the fifth, seventh or ninth week of the pregnancy the embryo’s development stops and the woman experiences a missed abortion.
Only a sperm of normal morphology, i.e. with a head, neck and tail, and of progressive motility, should contain all the information necessary to produce an embryo “programmed all the way to the bassinet”, when combined with the information from a healthy egg.
The basic IVF treatment procedures lead to clinical pregnancy in approximately 25 to 27 % of cases. However, current reproductive medicine is able to increase the pregnancy probability significantly, employing highly specialized laboratory micromanipulation techniques with spermatozoa, oocytes or embryos. These techniques are never and nowhere in the world covered by health insurance.
If case of the male infertility factor it is always more suitable to select a quality spermatozoon and inject it into the cytoplasm of the oocyte. This injection of a selected sperm to the oocyte cytoplasm is called ICSI - (intracytoplasmic sperm injection).
When using ICSI both the oocyte and the spermatozoon are selected and connected. However, the combination of their genetic information cannot be influenced further. That remains a matter of coincidence. The ICSI principle itself, i.e. the selection of both the sperm and the egg, significantly increases the probability of a “favourable combination” and a perfect pregnancy, as opposed to IVF where even the quality of the connected cells is a matter of chance.
If there are no sperms present even in the epididymis, it is also possible to extract them directly from the testicles (Testicular Sperm Extraction – TESE).
The MESA and TESE procedures are performed in complete anaesthesia by a urology specialist.
Development of new cultivation media allowed for prolonged cultivation of the embryos in a laboratory (in vitro). Such extended culture allows for better assessment of the embryos. It is possible to set apart embryos whose development slows down or stops and select the embryo or embryos with adequate development for transfer. Their culture can be extended to up to 5 days following the oocyte collection via ovary puncture.
The decision which day of in vitro culture is the most suitable for embryo transfer depends on the number and development stages of individual embryos which may vary in different couples.
Extended cultivation of embryos exceeding 48 hours offers the following positives:
1. Endometrium preparedness is better in tune with embryo development. With standard embryo transfer on the second day after the follicular puncture, the embryo is actually inserted in the uterus two days earlier than it would have arrived through the uterine tube during natural pregnancy.
2. With extended cultivation it is possible to choose embryos showing more promising development. Imperfect embryos with unsuitable composition of chromosomes /genetic information from the sperm and the egg/ slow down and stop at lower development stages, e.g. as two or four cell embryos. Such defective embryos cannot be distinguished during the basic 48-hour culture.
3. A transfer of two embryos at a later development stage has the same probability of pregnancy as a transfer of thee or four embryos transferred following a standard two-day culture. The risk of multiple pregnancies – twins or triplets – is incomparably lower.
Only approximately one third of all embryos develop to the stage of blastocysts. This depends on various and largely unknown factors. The development potential of an embryo can never be predicted with certainty at the time of egg fertilization. Despite successful egg fertilization in a laboratory, further development of the embryo may stop gradually.
The lower the number of eggs retrieved during follicular puncture, the lower the chance that one or two embryos will develop to the stage of a blastocyst.
According to current results, the success rate with transfer of 1-2 embryos at later development stages exceeds 50 %.
On day three of in vitro cultivation, one cell (blastomer) can be gently removed from six- to eight-cell embryos. The retrieved cell is screened for the number of chromosomes /karyotype/. The diagnostic procedure takes 48 hours. Meanwhile, the embryo develops to the blastocyst stage; with a normal karyotype the chance for a physiological pregnancy is higher. A child from this embryo would have the same karyotype as the examined cell.
PGD also showed that even a defective embryo can develop to the stage of a blastocyst with normal appearance. This finding explains why blastocyst transfer does not guarantee a pregnancy.
PGD does not warrant the birth of a healthy child because over than two thirds of children with various congenital defects present a normal chromosomal makeup. The defects need not be related to chromosomes.
However, after a transfer of an embryo with a normal number of chromosomes, pregnancy is more probable.
Therefore, PGD, i.e. transfer of an embryo with normal number of chromosomes, does not guarantee pregnancy, but it prevents a transfer or cryopreservation of an embryo with a defective number of chromosomes.
During IVF, sperms are added to the retrieved eggs in a special plate and special media, but they have to penetrate the individual eggs by themselves. In case of men with normal sperm, the so-called normospermics, approx. 50% of retrieved eggs get fertilized in this way, i.e. even with normospermics, a quality sperm does not fertilize each egg.
The quality of sperm that penetrates into an egg during IVF is unknown. It remains a matter of coincidence.
Unfortunately, an abnormal spermatozoon may also penetrate the egg and fertilize it. An embryo may develop even from such an abnormal sperm and the woman may get pregnant with such abnormal embryo. However, in the fifth, seventh or ninth week of the pregnancy the embryo’s development stops and the woman experiences a missed abortion.
Only a sperm of normal morphology, i.e. with a head, neck and tail, and of progressive motility, should contain all the information necessary to produce an embryo “programmed all the way to the bassinet”, when combined with the information from a healthy egg.
The basic IVF treatment procedures lead to clinical pregnancy in approximately 25 to 27 % of cases. However, current reproductive medicine is able to increase the pregnancy probability significantly, employing highly specialized laboratory micromanipulation techniques with spermatozoa, oocytes or embryos. These techniques are never and nowhere in the world covered by health insurance.
ICSI
If the infertility of a couple is influenced by the male factor, which is the case in approximately 60 % of couples, the IVF itself does not ensure success. Sperms either do not fertilize the eggs at all or eggs get penetrated by non-quality sperms.If case of the male infertility factor it is always more suitable to select a quality spermatozoon and inject it into the cytoplasm of the oocyte. This injection of a selected sperm to the oocyte cytoplasm is called ICSI - (intracytoplasmic sperm injection).
When using ICSI both the oocyte and the spermatozoon are selected and connected. However, the combination of their genetic information cannot be influenced further. That remains a matter of coincidence. The ICSI principle itself, i.e. the selection of both the sperm and the egg, significantly increases the probability of a “favourable combination” and a perfect pregnancy, as opposed to IVF where even the quality of the connected cells is a matter of chance.
IMSI
Because medicine today cannot effectively cure non-quality sperm production, it searches for techniques of quality sperm selection. The most important criterion for sperm quality is their morphology, i.e. their appearance. Therefore, a microscope has been developed which can enlarge the sperm up to 6000 times. A normal sperm moves progressively forward and it would disappear fast from the field of vision of the microscope with such magnification. A special computer technique records a picture of the sperm and allows a more detailed examination of its morphology. This method is called IMSI (intracytoplasmic morphologically selected sperm injection). At present, there are not enough data available to prove that this more thorough selection of spermatozoa really leads to a higher number of children born.MESA, TESE
If no spermatozoa are present in the ejaculate, it is sometimes possible to acquire them from the epididymis (Microsurgical Epididymal Sperm Aspiration – MESA) for the injection of a sperm to the oocyte (ICSI).If there are no sperms present even in the epididymis, it is also possible to extract them directly from the testicles (Testicular Sperm Extraction – TESE).
The MESA and TESE procedures are performed in complete anaesthesia by a urology specialist.
Extended culture
Until 1998, embryos were transferred after a two-day culture, in the stage of four cells per embryo, which is still considered a standard procedure. However, the stage of four cells can be reached by numerous potentially defective embryos and it is virtually impossible to distinguish a quality embryo at this early stage. |  |  |
Development of new cultivation media allowed for prolonged cultivation of the embryos in a laboratory (in vitro). Such extended culture allows for better assessment of the embryos. It is possible to set apart embryos whose development slows down or stops and select the embryo or embryos with adequate development for transfer. Their culture can be extended to up to 5 days following the oocyte collection via ovary puncture.
 |  |  |
The decision which day of in vitro culture is the most suitable for embryo transfer depends on the number and development stages of individual embryos which may vary in different couples.
Extended cultivation of embryos exceeding 48 hours offers the following positives:
1. Endometrium preparedness is better in tune with embryo development. With standard embryo transfer on the second day after the follicular puncture, the embryo is actually inserted in the uterus two days earlier than it would have arrived through the uterine tube during natural pregnancy.
2. With extended cultivation it is possible to choose embryos showing more promising development. Imperfect embryos with unsuitable composition of chromosomes /genetic information from the sperm and the egg/ slow down and stop at lower development stages, e.g. as two or four cell embryos. Such defective embryos cannot be distinguished during the basic 48-hour culture.
3. A transfer of two embryos at a later development stage has the same probability of pregnancy as a transfer of thee or four embryos transferred following a standard two-day culture. The risk of multiple pregnancies – twins or triplets – is incomparably lower.
Only approximately one third of all embryos develop to the stage of blastocysts. This depends on various and largely unknown factors. The development potential of an embryo can never be predicted with certainty at the time of egg fertilization. Despite successful egg fertilization in a laboratory, further development of the embryo may stop gradually.
The lower the number of eggs retrieved during follicular puncture, the lower the chance that one or two embryos will develop to the stage of a blastocyst.
According to current results, the success rate with transfer of 1-2 embryos at later development stages exceeds 50 %.
PGD
Extended culture offers patients with congenital chromosome defects a possibility of so-called pre-implantation genetic diagnosis (PGD). PGD represents a screening for the number of chromosomes in the embryo prior to its transfer to the uterus, i.e. before implantation.On day three of in vitro cultivation, one cell (blastomer) can be gently removed from six- to eight-cell embryos. The retrieved cell is screened for the number of chromosomes /karyotype/. The diagnostic procedure takes 48 hours. Meanwhile, the embryo develops to the blastocyst stage; with a normal karyotype the chance for a physiological pregnancy is higher. A child from this embryo would have the same karyotype as the examined cell.
PGD also showed that even a defective embryo can develop to the stage of a blastocyst with normal appearance. This finding explains why blastocyst transfer does not guarantee a pregnancy.
PGD does not warrant the birth of a healthy child because over than two thirds of children with various congenital defects present a normal chromosomal makeup. The defects need not be related to chromosomes.
However, after a transfer of an embryo with a normal number of chromosomes, pregnancy is more probable.
 |  |  |  |
Therefore, PGD, i.e. transfer of an embryo with normal number of chromosomes, does not guarantee pregnancy, but it prevents a transfer or cryopreservation of an embryo with a defective number of chromosomes.
Assisted hatching (AH)
The human egg is covered with an elastic outer shell called zona pellucida. This shell also covers the developing embryo. Before the embryo implants in the endometrium, it must “break free” from its covering. This process is called hatching. The assisted hatching facilitates the nidation of the embryo in the uterus. In the laboratory, the cover is cut by means of a laser or a very fine glass needle (micropipette), which allows the embryo to hatch easily through this opening. The puncture from the previous sperm injection during ICSI is insufficient in most cases and cannot replace assisted hatching. The embryo is not damaged by the assisted hatching procedure. |  |  |  |
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