What Is In Vitro Fertilization (IVF)? Explained in Details

 Explained in Details: In Vitro Fertilization Program

The in vitro fertilization process begins with selecting the patient for a program of controlled ovarian hyperstimulation and in vitro fertilization. This selection is made based on the couple’s diagnosis of infertility. The process begins with ovarian hyperstimulation, which aims to produce more follicles and fertilizable ovules.

In this way, several embryos are transferred to each patient and a greater possibility of pregnancy than with a non-stimulated cycle. Gonadotropin-releasing hormone analogs are also used concomitantly. During the process of controlled ovarian hyperstimulation with gonadotropins, the following steps are followed until the ovules are aspirated for in vitro fertilization.

1- Ovarian hyperstimulation with gonadotropins by injecting hormones intramuscularly.

2- Serial transvaginal ultrasound to measure the sizes of the developing follicles and the formation of the trilaminar endometrium.

3- Daily measurements of estradiol as adjuvants to determine follicular maturity.

4- Once the majority of the follicles reach sizes of 18 to 20 mm, gonadotropins are suspended, and 10,000 units of Human Chorionic Gonadotropin are applied intramuscularly to provoke the final shedding of the developing follicles.

5- 34-36 hours after applying the Human Chorionic Gonadotropin injection, aspiration of the follicles is preceded by transvaginal route in the operating room adjacent to the In Vitro Fertilization laboratory. For this, a 5 Mhz transvaginal probe is used with a guide programmed on the screen to insert the needle that will collect the ovules inside each follicle.

6- Once the ovules have been collected, they are recognized in the embryo culture area within the In Vitro Fertilization laboratory.

7- The recognition of the ovules is carried out under the magnifying glass of a dissection microscope placed inside a Laminar Flow chamber.

8- Once the ovules have been recognized and deposited in a culture medium, they are inseminated 4 hours later with the husband’s semen.

9- There are two ways to inseminate the ovules. Each depends on the degree of severity of male infertility.

10- The first is conventional in vitro fertilization, which consists of leaving the ovules and sperm in culture overnight so that the penetration of the sperm occurs equally.

11- The other way is ICSI (intracytoplasmic sperm injection) ICSI is used for very severe infertility of male origin; It consists of taking a single sperm and injecting it into the egg. This is achieved by the micromanipulation technique under the direct vision of an inverted microscope. After the injection, the fertilization of the ovum is evaluated the following day.

12- The next day (20 hours) after insemination, by ICSI or conventional, we must have pre-embryos in a state of 2 pronuclei (fertilized).

13- 48 hours after insemination, embryos of 4 to 6 cells should be obtained. These embryos are introduced into the woman’s uterine cavity through special catheters. We will realize 12 days later if pregnancy occurs because we have a positive pregnancy test.

14- Some cases require that the embryos be transferred not at 48 hours but on the fifth day. These cases are called blastocyst stage transfer and are used for patients at risk of multiple pregnancies or with repeated implantation failures at 48 hours.

Embryo Biopsy

Another procedure performed in the in vitro fertilization laboratory is embryo biopsy. Embryo biopsy is generally used to make a genetic diagnosis of embryos from couples who are at risk of having children with congenital abnormalities. This evaluation is done before transferring the seeds to the mother. This ensures that only genetically normal embryos will be shared. Embryo biopsy is performed with the same micromanipulator and inverted microscope used to perform ICSI.

The only thing that varies is special micropipettes different from those used in ICSI. Embryo biopsy consists of extracting a cell with its nucleus called blastomere from the embryo at a state of 6-8 cells (third day of development in vitro). This removal does not affect the developing embryo at all. The blastomere analysis takes a few hours, and the results can be given the same day or the day after the biopsy. In this way, normal embryos are transferred; genetically on the fourth day of development, which guarantees the mother a healthy fetus without genetic abnormalities.

About the IVF Laboratory

The In Vitro Fertilization Laboratory consists of 4 areas.

1- Dressing room: area in which patients change into suitable clothes for follicular aspiration or embryo transfer.

2- Recovery: area in which patients rest for a period of up to one hour after follicular aspiration.

3- Operating room: area in which follicular aspiration guided by transvaginal ultrasound is performed. It is also used to perform embryo transfers and diagnostic procedures such as laparoscopy and hysteroscopy.

4- Embryo culture: area in which the oocytes that have been aspirated in the operating room are received for their subsequent recognition and insemination. In this area, the embryos obtained remain in culture from 48 hours to 5 days before being transferred to the mother. It is also an area where surplus embryos are frozen and stored indefinitely for later use.

IVF Laboratory Specifications

1- It must be a sterile area.

2- It consists of a positive pressure air conditioning system with high-efficiency HEPA filters on the rest of the                   regions. It also has aluminum ducts to prevent the detachment of particles from conventional ducts.

3- The four adjacent areas have independent air outlets and return systems.

4- The walls, floors, and furniture must be covered or made of non-toxic and washable materials.

5- Soaps should not be used for cleaning. Daily cleaning is done with sterile water. Work surfaces are sterilized with         70% alcohol.

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