Since a large number of egg cells are ready to grow at the beginning of the menstrual period, if we can increase the amount of FSH hormone produced by the brain to grow these egg cells, other egg cells that cannot be used under normal conditions due to the limited amount of FSH hormone produced by the body will also grow.
There are 2 methods for large number of follicles to grow:
1. To ensure more FSH production from the brain more than the pituitary gland: For this, medicines in tablet forms are used. However, growth of 5 or more follicles in this way is rare.
2. Supplementing the FSH hormone from outside: For this purpose, FSH hormone is used in the form of an injection and if the ovarian reserve is good depending on the preferred dose, 10-15 follicles are enlarged to obtain a large number of egg cells.
In most IVF trials, the use of FSH hormone in needle form is preferred.
The process of ensuring the maturation of more than one egg cell in the ovaries by externally giving FSH hormone or by enabling the body to produce more FSH hormone is called stimulation of the ovaries. Scientific studies show that in vitro fertilization trials in which the ovaries are stimulated with medication are more successful.
The stimulation of the ovaries is usually started on the 2nd or 3rd day of menstruation. In order to follow the response of the ovaries, the expectant mother is followed by ultrasound examination and, when necessary, blood hormone measurements. The main hormone released from the growing follicles is the estrogen hormone. Follicle diameters are expected to increase at each appointment compared to the previous appointment, and estrogen hormone levels are expected to double every two days.
Cessation of follicle growth or unexpected decreases in estrogen hormone levels during follow-up can negatively affect success. For this reason, treatment can even be canceled.
In the follow-ups, in addition to the growth of the follicles, it is checked whether the intrauterine membrane tissue, in other words the endometrium, is thick enough. When embryos are released into the intrauterine cavity, the thickness of the membrane covering this cavity is of great importance in the formation of pregnancy. In cases where the endometrium is not thick enough, embryos are frozen and stored when necessary, and are not transferred. The reason for the failure of the intrauterine membrane to thicken is investigated, then the intrauterine membrane is thickened with drugs and the stored embryos can be thawed and transferred.
During the stimulation of the ovaries, ultrasound examinations are used to determine whether the follicles are growing in a certain rhythm and whether the intrauterine membrane is thick enough.
With a 8-10 days of drug use, egg cells in the growing follicles reach maturity where they can be fertilized by the sperm. Now the egg cells are ready to be collected.
The process of collecting the egg cells can be done with or without putting the expectant mother to sleep. It takes about half an hour. After the procedure is completed, you can be discharged after a 2-3 hour rest.
Egg collection is performed under the guidance of vaginal ultrasound. Vaginal ultrasound allows imaging of the growing follicles in the ovary. The follicles viewed with ultrasound are entered vaginally with a specially produced needle with a very thin tip. This needle is attached to a device that acts as a vacuum with a special thin plastic tube. With the pulling power of the needle, the liquid and egg cells in the follicle are absorbed and taken into special tubes.
Each egg cell obtained may not be used in IVF procedure. Eggs of sufficient maturity and good quality are separated from the obtained egg cells and prepared for in vitro fertilization.
On the day of egg collection, sperm is taken from the future father. Mobile and structurally healthy sperm are separated by special laboratory methods. The reason for IVF application is female-related reasons, if there is no problem with the number, movement or structure of the sperm, then classical IVF is preferred.
In the classical fertilization, the egg cell is enclosed in a special liquid prepared in the form of a water droplet called medium in special round containers. This liquid contains nutrients for the egg cell. A certain number of sperm are left around the egg cell. The sperm and egg are kept overnight in this liquid in special cabinets imitating the body in terms of temperature and gas, which is called an incubator. The next day, whether or not fertilization occurred is checked.
SPERM INSEMINATION OF EGG CELL USING THE CLASSIC METHOD
Micro-injection Technique in IVF Treatment
In IVF treatment, the egg cells taken from the woman and the sperm cells taken from the male are brought together in the laboratory environment and fertilization is facilitated. The embryos obtained here are allowed to develop in the laboratory environment. Finally, the highest quality embryos are selected and transferred to the mother's womb.
In the micro-injection (ICSI) technique, a healthy sperm cell selected from the sperm sample taken from the father is injected into the egg with a thin needle, under the microscope. When applying the micro-injection method, firstly the best quality sperm in the semen are preferred. While the pre-selected sperm cells are in a special needle (glass pipette), the membrane of the egg is pierced and the sperm is injected into it. Since this process is performed under a microscope, it is called micro-injection. After each egg is combined with a single sperm, it is placed in special cabinets. The next day, it is checked whether or not the sperm fertilized the egg. After that, fertilization is expected. The stages after the sperm and egg are combined proceed as in classical IVF treatment.
In micro-injection technique, the sperm does not fertilize the egg cell automatically, it is placed into the egg cell with intervention. Therefore, the probability of fertilization is much higher. In the micro-injection method, even a single sperm will be sufficient for fertilization. In patients with azoospermia (no sperm in the semen), fertilization can occur with sperm cells obtained from the testicles.
The micro-injection method was first applied in our country in 1992. Micro-injection method has been accepted as a revolution for problems such as structural disorders in sperm, low mobility and insufficient sperm count in men.
Micro-injection method is also used in cases where the egg shell of the expectant mother is too thick or hard to allow sperm or in expectant mothers whose egg reserve has decreased due to advanced age.
Micro-injection technique is preferred for men with low sperm count, insufficient (less than 10 percent) motile sperm, defects in the structure of the sperm and for men with no sperm in the semen where sperm are obtained from the testicles.
In micro-injection technique, fertilization is expected after a single sperm is injected directly into the egg. In classical IVF treatment, multiple reproductive cells are brought together in a laboratory environment and the sperm is expected to fertilize the egg cell on its own.
Apart from this, there is no difference between in vitro fertilization and micro-injection technique. The difference is only in the way the egg is fertilized.
Today, micro-injection method is preferred in many IVF centers. The reason for this is that in the micro-injection technique, the possibility of fertilization is high as the sperm cell is directly injected into the egg.
The situations where micro-injection (ICSI) technique is used:
The zygote is formed as a result of the fertilization of the sperm and egg. When the zygote begins to divide into cells, it becomes an embryo.
If we accept the day of insemination in IVF as day 0, we determine how many of the egg cells treated on the next day, i.e. the 1st day, become zygotes, that is, fertilized.
It is not enough for the egg to form a zygote by fertilization with sperm. The zygote must divide into cells to form the embryo.
If we remember pregnancy in the natural process, the sperm and the egg cell meet in the tube, the sperm enters the egg by piercing the outer membrane of the egg and fertilization occurs. When fertilization occurs by combining sperm and egg, the zygote is formed. As the resulting zygote rolls through the tube towards the uterus, cell division begins, cell division continues inside the tube, and after a 5-day journey, the embryo reaches the intrauterine cavity and is embedded in the uterine tissue and pregnancy occurs.
Embryo culture is the laboratory imitation of this natural process that we mentioned above. Here, embryos are stored in special cabinets that we call incubators. The temperature of these cabinets is adjusted to body temperature, and the amount of oxygen, carbon dioxide and nitrogen gases inside the incubator are similar to the amounts in the Fallopian tube. In summary, incubators mimic the tube environment. Embryos are monitored in these cabinets in medium droplets. The medium is made up of specially produced fluids that contain nutrients that allow the embryo to live outside the body.
Every day the development of the embryos is monitored. Every day, the cell divisions and whether the divided cells are of equal size are monitored under the microscope, provided that the embryos are removed from the incubator and remain in the droplets.
Of course, the development of every embryo will not be the same. In fact, this elapsed time spent outside the body enables the identification of better quality embryos.
Embryo transfer is a procedure that does not require anesthesia. We want the expectant mother to be full of urine during this procedure. Thus, the position of the uterus becomes suitable for transfer, and a quality ultrasound image is provided to place the embryos in the region of the uterus with the highest pregnancy probability.
Before the procedure, the expectant mother's bladder becomes full by drinking water. After urinary congestion is achieved, the expectant mother is taken to the procedure room. Urine congestion is checked by ultrasound. If the tightness is suitable, the cervix is seen by entering the vagina with a special tool called a speculum. Afterwards, the vagina and cervix are cleaned with a special liquid that we call a medium. The secretions in the uterine canal are cleaned if necessary.
The name of the mother and father is verified. The embryos selected for transfer are enclosed in a special plastic cannula that we call a catheter. The embryo or embryos are inserted into the uterus with ultrasound guidance through the cervical canal and placed in the appropriate area in the upper half of the uterus where the thickness of the uterine membrane is appropriate.
After that, an exciting and hopeful process begins for the pregnancy test results.
Here, the number of fertilized eggs we have and the number of first quality embryos are determinant. Let's explain with an example.
Let's assume that 3 eggs are obtained from our expectant mother and two of them are fertilized. If we have 2 embryos that we can transfer, these embryos should be transferred to the ideal environment in the body as soon as possible. Since there are not many alternatives to choose from, early transfer is made.
Let's assume that 6 of the eggs obtained from the mother are fertilized, in this case, we keep the embryos preferably until the 3rd day. If 2 embryos are to be transferred according to the age of the patient, the best 2 embryos can be selected and transferred on the 3rd day and the remaining embryos can be frozen. If a single embryo is to be transferred and we have 3 or more quality embryos, then the embryos are transferred by waiting until the 5th day, that is, the blastocyst stage.
Embryo reaches the blastocyst stage about 5 or 6 days after fertilization. The embryo, which reaches this stage, gets rid of the outer shell, which we call Embryo zona, first attaches to the inner surface of the uterus and then is buried. This event is called implantation.
Embryo transfer, fertilization of sperm and egg can be done on the second, third, fourth and fifth days. Embryos transferred into the uterus before the fifth day, do not attach to the uterus on the day they are transferred. By continuing to divide within the uterus, they must reach the blastocyst stage. Some of the embryos transferred earlier than the 5th day stop developing in the uterus and cannot reach the 5th day, that is, the blastocyst stage.
Follow-up of embryos up to the blastocyst stage in the laboratory, especially in young mothers who are under 35 years of age and have the highest number of eggs; the transfer of embryos by selecting the ones that reach this stage will positively increase pregnancy rates.
The embryos who can run this marathon and reach the finish line have a higher pregnancy potential.
It should be noted that a conclusion should not be drawn that a blastocyst transfer should always be performed. The efficacy of blastocyst transfer is still controversial, especially in couples with a female aged 35 and over. It is not enough for an embryo to only reach the blastocyst stage. Blastocysts also have a quality classification among themselves. Pregnancy rates are not the same according to this quality classification. Continuing the blastocyst stage and transferring a single embryo will reduce the risk of multiple pregnancy in couples in which the woman is under 35 years of age and who have a sufficient number of quality embryos on the 3rd day.
What is an embryoscope?
In order to decide which of the embryos obtained by fertilization of sperm and egg in the laboratory environment are to be transferred to the uterus, their development should be followed. During this follow-up, embryos are kept in special cabinets, which we call incubators, whose temperature, humidity and gas rates are specially adjusted and resemble the female genital system. In the daily monitoring of the embryos, the embryos are taken from these cabinets for a short time. Under the microscope, the development of cell divisions is noted. However, leaving the incubator, even for a short time may adversely affect the embryos.
Considering this problem, special incubators have been developed that can monitor the 24-hour development of embryos and record images of their development.
In this way, embryos can be followed without ever taking them out of the incubator, and embryos that divide earlier and whose cell divisions do not have a problem are better identified with this observation, making it easier to select the right embryos.
In other words, of the two embryos with the same number of cells, which one has divided first, whether the cell division is stable or not, in this way, can be understood better.
In a conventional incubator, the current state of the embryo is seen and an instant decision is made. This decision and choice can be highly accurate.
The chance of pregnancy can be increased by embryo selection made by processing the embryos with an embryoscope. However, there is no strong scientific evidence for this yet. This method should not be considered as a miraculous method.
The IMSI method is a method used especially for structural problems in sperm. The head of the sperm contains the genetic structure that we call the nucleus. It carries z gene segments that we call nucleus DNA. Especially the cases in which the vacuoles in the sperm head area may indicate damage to the DNA, or genes, in these sperms.
Microscopes with approximately 600 times magnification are used when selecting sperm for fertilization. Vacuoles may not always be detected with these microscopes. In this case, a selection can be made by enlarging the sperm head up to 6000 times with a special optical system. Here, we call it IMSI in which sperm selection is made by using greater magnification for fertilization with eggs and micro-injection of these sperms to the eggs.
IMSI is not required for every couple.
In men who have no sperm in their semen, there may be sperm production in the testicles. The only way to tell if there is sperm production in the testicles is to take a tissue sample from the testicles.
Micro TESE is a special surgical method applied to the testicles. In this method, where a special surgical microscope is used, small tissue samples are taken from the areas of the testicles where sperm are most likely to be found.
In the testicles, sperms are produced in filamentous structures called TUBULES. TUBULES with sperm production appear more bloated than others. These plump tubules cannot be distinguished visually. For this reason, a special microscope is used to further enlarge the testicular tissue. Under the guidance of a microscope, tubules that are plump are selected, taken with special fine tweezers, and they are crushed by special methods in the IVF laboratory and the presence of sperm is investigated. When sperm is obtained, these sperms are separated for use in the fertilization process of the egg.