Sexually Transmitted Diseases - I. I. Mavrov 2005

Infertility
In vitro fertilization and embryo transfer

Human in vitro Fertilization (IVF) and embryo transfer (ET) into the Uterus are performed according to standard indications, specifically: tubal infertility caused by occlusion or absence of the fallopian tubes; prior reconstructive tubal surgery, particularly if the female patient is over 30 and at least one year has elapsed since the Procedure; unsuccessful salpingolysis or ovariolysis, generally in women over 35; certain forms of Endometriosis; unexplained infertility; male factor infertility; and immunological infertility in women with persistently high levels of antisperm Antibodies for one year (C. Campagnoli et al., 1985).

Recently, IVF has been very successfully applied as a Treatment for infertility. It can be stated that the technical aspects of this problem have been satisfactorily resolved, yielding encouraging results. For instance, I. Steptoe and A. Edwards (1979) reported that the success rate of in vitro fertilization for preovulatory oocytes is 70–80%, and that approximately 90% of fertilized eggs develop into embryos capable of normal implantation in tissue culture. Furthermore, the authors noted the good condition of the embryos during five days of in vitro culture.

However, these data characterize only the preparatory phase prior to embryo transfer. When such embryos are transferred into the uterus during the early luteal phase of a natural Menstrual cycle in women lacking tubal function, Pregnancy occurs only in rare instances. Therefore, the processes of in vitro fertilization and uterine embryo transfer for the treatment of infertile couples must be organized and conducted to ensure a close connection between the preparatory phase and the transfer program.

In this regard, it is necessary to consider: determining the indications for IVF and ET; applying treatment regimens that ensure the effective performance of medical personnel; and assessing the practical feasibility of the procedure based on an analysis of success rates and fetal pathology cases. Contraindications for IVF and transfer include: advanced maternal age (over 40 years), Male infertility with pronounced pathological Changes in the spermogram, and genetic Selection criteria (hypospadias, Congenital Heart defects, Schizophrenia, affective psychosis, multiple sclerosis, a family history of Autosomal Recessive Disorders, dominantly inherited diseases, etc.).

Most experts believe that an IVF and ET center team should consist of physicians, nurses, a psychologist, and a sociologist. They must address a range of issues related to treatment modalities as well as psychological and social complications. This places high demands on both the staff and the patients themselves. The goal of a prolonged IVF and ET program is to bring patients to the point of transfer in good general condition. Throughout treatment, patients typically experience hope combined with the fear of failure. Moreover, failure at any stage of treatment can be extremely difficult for them to accept, despite previous assurances that they fully understand how slim the chances of success are. Therefore, psychological disturbances must be continually addressed. The criterion for rehabilitation is not only the onset of pregnancy but also its full-term delivery.

The male partner from a couple selected for IVF and ET treatment undergoes a comprehensive semen analysis 2 to 3 months prior to active therapy, including bacteriological testing to rule out Sexually Transmitted Infections. Simultaneously, both partners are screened for infections (gonococcal, trichomonal, chlamydial, ureaplasma, viral, fungal, etc.) that could contaminate the fertilization cultures and cause complications following embryo transfer. Cervical malignancies are also ruled out.

During the menstrual cycle preceding the oocyte retrieval cycle, the duration of the follicular phase is determined. In regular menstrual cycles, selective examination of cervical mucus begins on cycle day 9, and once its secretion starts to increase, daily urinary estrogen levels are determined to establish the timing and amplitude of the preovulatory peak. Subsequently, estrogen and pregnanediol excretion are measured in the middle of the luteal phase to confirm ovulation. If an anovulatory menstrual cycle is detected, consideration is given to conducting another study cycle or referring the patient for in vitro fertilization (A. Lopata et al., 1980).

During the preovulatory phase of the cycle, Blood samples are drawn to prepare embryo Culture Media and to conduct Laboratory tests to rule out Toxoplasmosis, rubella, cytomegalovirus, hepatitis B, herpesvirus infection, and Syphilis. Chromosomal blood testing is also performed to identify individuals at increased risk of producing aneuploid Gametes. Blood serum is tested for sperm antibodies and zona pellucida antibodies. During the preliminary examination stage, the lengths of the cervical canal and uterine cavity are measured using a uterine probe in preparation for subsequent catheter-based embryo transfer.

Various protocols for ovulation induction (superovulation) are used for in vitro fertilization, including combinations of clomiphene, hMG, and hCG; hMG alone; FSH and hMG; or clomiphene alone. Across all ovulation induction protocols, monitoring begins on day 7 and includes plasma estradiol level determination, ultrasound, and cervical mucus evaluation. For successful IVF, it is recommended to monitor follicular GROWTH AND DEVELOPMENT via ultrasound, determine levels of E2, progesterone, and LH, and assess the individual response to stimulation.

Ovulation induction is discontinued if: 1) a peak LH level is detected prior to ovulation; 2) the diameter of the dominant follicle is less than 21 mm; 3) progesterone levels rise without an increase in LH levels; 4) the number of follicles is less than 6; 5) an LH peak is detected in the presence of more than 5 follicles; or 6) dominant follicles with a diameter greater than 21 mm appear before peak progesterone levels are reached (P. Kemeter, W. Feichtinger, 1985).

Currently, the method of choice is to obtain oocytes for subsequent IVF via aspiration during natural, unstimulated menstrual cycles, as ovarian stimulation can be a cause of failures occurring in pregnancies resulting from The transfer of embryos derived from stimulated oocytes.

Oocyte retrieval is performed via laparoscopy, or less frequently via laparotomy during tubal surgery (V. I. Hryshchenko et al., 1986). Transvaginal or transvesical ultrasound-guided follicular puncture is also utilized. Today, this method is considered optimal—it simplifies oocyte recovery, reduces risk to the patient, is convenient even in the presence of adhesions, and can be performed on an outpatient basis (B. V. Leonov et al., 1987; J. Cohen et al., 1986, etc.). The oocyte is washed twice with fertilization medium to remove the bulk of the follicular fluid. It is then transferred into a droplet of equilibrated fertilization medium under sterile paraffin oil. Tyrode's solution containing Pyruvate, albumin, and Antibiotics is used as the fertilization medium (A. Edwards et al., 1979; A. Lopata et al., 1980).

Fresh semen, taking into account its liquefaction at room Temperature, is diluted in two washes of fertilization medium. Seminal plasma is removed as follows: a small amount of semen is diluted in a fourfold volume of fertilization medium, the sperm suspension is centrifuged (200 G), the supernatant is removed, the sperm pellet is resuspended, and the procedure is repeated. The sperm pellet obtained in this manner is resuspended once again, and their concentration and motility are determined and adjusted to standard values required for the oocyte fertilization procedure.

A known volume of the sperm suspension is added to the medium droplet containing the oocyte. The insemination droplet typically contains 1.0–1.5 × 10⁶ spermatozoa per 1 mL and is incubated at 37 °C at pH 7.6 in an atmosphere containing 5% CO₂, 5% O₂, and 90% N₂. The oocyte is left in the sperm suspension for 6–18 hours. Thereafter (approximately 12–18 hours post-insemination), signs of fertilization can be identified using a Microscope: male and female pronuclei are visible in the Cytoplasm. Normal embryonic development in culture is indicated by the appearance of dividing Cells of approximately equal size and shape that evenly fill most of the space within the zona pellucida. The growing human embryo is cultured at 37 °C in an atmosphere containing 5% CO₂, 5% O₂, and 90% N₂ in a medium with pH 7.3. The pre-implantation embryo is kept in Cell culture for 2–3 days.

Transfer is performed as follows: the embryo in 0.5 mL of culture medium is gently drawn into a sterile 1.4 mm diameter catheter. The catheter is then guided through the cervical canal into the uterine cavity, where the embryo is expelled from the catheter near the fundus. To facilitate this procedure, the catheter should be marked along its length to monitor THE POSITION OF its tip within the uterine cavity. In addition, it must be manipulated very carefully to avoid contractions of the uterine cervix. Embryo transfer is preferably performed in the evening (J. Steptoe, A. Edwards, 1979).

Currently, IVF and ET represent a promising yet rather complex and costly method for treating certain forms of male and Female Infertility. It yields relatively good results, which depend on determining the optimal timing for mature oocyte retrieval, quantitative and qualitative semen assessment, the results of medical-genetic screening of the couple, the precision of all procedural techniques, and accounting for the PHYSIOLOGICAL AND BIOCHEMICAL processes occurring during embryo implantation.

Among the drawbacks of the IVF and ET method are that only 55–60% of pregnancies resulting from IVF and ET culminate in the birth of viable children; 1.5% to 8% of pregnancies are ectopic; spontaneous abortions occur in 18–20% of women; biochemical pregnancy (blighted ovum) develops in 15–18%; premature births occur 3 times more frequently than in the general pregnant population; and low birth weight is observed more often than in healthy women.

However, there is every reason to expect that progress will be made in this direction, both in the techniques and in the physiology and biochemistry of in vitro fertilization and uterine embryo transfer. Advancements in biology and physics have facilitated the rationale and development of human oocyte cryopreservation Methods. Accumulated experience to date indicates a high pregnancy rate following early embryo freezing. The success of this endeavor is exceptionally important not only for science, but also for medical practice in combating infertility.