**2. In vitro fertilization and known reasons that reduce its efficacy**

In vitro fertilization of preovulatory oocytes and transfer of cleaving embryos into the patient's uterine cavity has become the prevalent method to overcome the problem of infertility (Pioneers in in vivo Fertilisation .., 1995). The IVF method was initially devised for those women whose Fallopian tubes were removed for one reason or another. However, at present, IVF is the most effective treatment for virtually all types of infertility, including endometriosis, polycystic ovary syndrome, oocyte donation (in infertile patients with oogenesis depletion), fertilization of an egg with a single sperm in cases of virtually absolute forms of male infertility (intracytoplasmic sperm injection - ICSI), carriage of an embryo by a voluntary egg recipient when a woman cannot carry the pregnancy due to some somatic or other diseases (Maheshwari et al., 2008). Despite all achievements, the IVF pregnancy rate is comparatively low. It ranges from 25% to 30% and has not changed considerably in recent years (Nyboe Andersen et al., 2009). This rate relates to a number of diverse factors that affect the reproductive process. Implantation failure following embryo transfer is the major problem in IVF (Bischof et al., 2006; Christiansen et al., 2006). IVF failures may be caused by a variety of factors: diminished ovarian reserve, maternal and paternal age, excessive body weight, endocrine disorders in the hypothalamus-pituitary-ovary system, as well as in the suprarenal and thyroid systems, diminished endometrial receptivity, quantity and quality of transferred embryos, number of transfers, and thrombophilic disorders.

*Ovarian reserve.* Ovarian reserve is one of the factors that determine the efficacy of IVF (Gregory, 1998; Navot et al., 1987; Scheffer et al., 2003). Assessing the ovarian reserve, specialists draw conclusions based on the prospects of ovarian stimulation in a particular patient. Conclusions may be used to define a specific procedure and further treatment prospects, as well as to make the right choice of the ovarian stimulation scheme and the quantity of drugs of human menopausal gonadotropin or follicle-stimulating hormone (FSH), which are necessary for an adequate response. The routine method for assessing the ovarian reserve measures basal FSH level on the 3rd or 4th day of the menstrual cycle and estimates the quantity of antral follicles with ultrasonography. However, at present, the prognostic significance of ultrasonography is considered less informative, even though it reflects the quantity and quality of oocytes (Damti et al., 2008). The role of new factors capable of reflecting the functional status of the ovary in a more precise manner is under discussion. (Gregory, 1998).

*Maternal and paternal age.* Lintsen et al. (2007) concluded that the most important prognostic indicator to define the probability of pregnancy after IVF and ICSI is maternal age ( more frequently observed positive results -in 30-year-old women, less frequently - in women under 35, and least frequently - in women over 35). Physiological process of the gradual decline of ovarian function is one of the key obstacles for the efficacy of IVF, which depends on maternal age, current condition of the ovarian reserve and to a lesser extent on chosen schemes of ovulation induction. The cases of women under 41 are treated as relatively promising, to reason the use of donated oocytes in older women (Maheshwari et al., 2008). Paternal age also affects the conception rate: it shrinks with men after 35 due to the quality of sperm to have been deteriorated by this age (Saleh et al., 2002).

78 Enhancing Success of Assisted Reproduction

discussion. (Gregory, 1998).

Treatment of Infertility, LLC (Moscow), International Center for Reproductive Medicine (Saint-Petersburg), the Baltic Institute of Human Reproductology (Saint-Petersburg), etc.

In vitro fertilization of preovulatory oocytes and transfer of cleaving embryos into the patient's uterine cavity has become the prevalent method to overcome the problem of infertility (Pioneers in in vivo Fertilisation .., 1995). The IVF method was initially devised for those women whose Fallopian tubes were removed for one reason or another. However, at present, IVF is the most effective treatment for virtually all types of infertility, including endometriosis, polycystic ovary syndrome, oocyte donation (in infertile patients with oogenesis depletion), fertilization of an egg with a single sperm in cases of virtually absolute forms of male infertility (intracytoplasmic sperm injection - ICSI), carriage of an embryo by a voluntary egg recipient when a woman cannot carry the pregnancy due to some somatic or other diseases (Maheshwari et al., 2008). Despite all achievements, the IVF pregnancy rate is comparatively low. It ranges from 25% to 30% and has not changed considerably in recent years (Nyboe Andersen et al., 2009). This rate relates to a number of diverse factors that affect the reproductive process. Implantation failure following embryo transfer is the major problem in IVF (Bischof et al., 2006; Christiansen et al., 2006). IVF failures may be caused by a variety of factors: diminished ovarian reserve, maternal and paternal age, excessive body weight, endocrine disorders in the hypothalamus-pituitary-ovary system, as well as in the suprarenal and thyroid systems, diminished endometrial receptivity, quantity and quality of

**2. In vitro fertilization and known reasons that reduce its efficacy** 

transferred embryos, number of transfers, and thrombophilic disorders.

*Ovarian reserve.* Ovarian reserve is one of the factors that determine the efficacy of IVF (Gregory, 1998; Navot et al., 1987; Scheffer et al., 2003). Assessing the ovarian reserve, specialists draw conclusions based on the prospects of ovarian stimulation in a particular patient. Conclusions may be used to define a specific procedure and further treatment prospects, as well as to make the right choice of the ovarian stimulation scheme and the quantity of drugs of human menopausal gonadotropin or follicle-stimulating hormone (FSH), which are necessary for an adequate response. The routine method for assessing the ovarian reserve measures basal FSH level on the 3rd or 4th day of the menstrual cycle and estimates the quantity of antral follicles with ultrasonography. However, at present, the prognostic significance of ultrasonography is considered less informative, even though it reflects the quantity and quality of oocytes (Damti et al., 2008). The role of new factors capable of reflecting the functional status of the ovary in a more precise manner is under

*Maternal and paternal age.* Lintsen et al. (2007) concluded that the most important prognostic indicator to define the probability of pregnancy after IVF and ICSI is maternal age ( more frequently observed positive results -in 30-year-old women, less frequently - in women under 35, and least frequently - in women over 35). Physiological process of the gradual decline of ovarian function is one of the key obstacles for the efficacy of IVF, which depends on maternal age, current condition of the ovarian reserve and to a lesser extent on chosen *Excessive body weight.* Menstrual dysfunction, polycystic ovary syndrome, hyperplastic processes in endometrium, infertility, miscarriage, gestoses, fetal hypotrophies, high rate of operative deliveries make up an incomplete list of reproductive disorders typical of obese women. 40% of women seeking for treatment of infertility in medical centers have excessive body weight; over 15% of such women are obese. The IVF program is preferable to start after the patient's body weight has become normalized; therefore, patients often fail to meet the required standards (Ku et al., 2006; Lintsen et al., 2005; Mc Clamrock, 2008; Megan et al., 2008). Status of the hypothalamus-pituitary-ovary system, suprarenal and thyroid systems. Interaction of the two key pituitary hormones - FSH and luteinizing hormone (LH) - is essential for the adequate growth of follicles, as well as for the formation of viable oocytes. Studies of ovulation induction in hypogonadotropic patients showed that exogenous FSH stimulates the growth of follicles up to the preovulatory stage and its synthesis primarily depends on LH, i.e. adequate maturation of follicles takes place due to this gonadotropin. Insufficient concentration of LH disturbs paracrine mechanisms regulating granulosa cells, as well as endometrial proliferation, and results in inadequate luteal phase (Alviggi et al., 2009; Balasch et al., 1995; Hull et al., 1994). Excessive concentration of LH also negatively affects the growth of follicles to be the result of suppressed aromatase activity, accompanied by fertilization disorders, decreased pregnancy rate decrease and increased miscarriage rate (Hillier, 1994). Thus, the threshold concentration (1-10 IU/l) is optimal for adequate folliculogenesis (Howles et al., 2006). It has been noted that low estradiol level in the blood serum (<200 pmole/l) on the 3rd day of the patient's menstrual cycle is a positive prognostic indicator of successful implantation in the IVF cycle. At the same time, some reports state that basal estradiol level was not a significant indicator of ovarian response to stimulation and did not correlate with the IVF result (Friedler et al., 2005). In recent years, researchers and clinicists have given a lot of consideration to the problem of thyroid gland dysfunction in infertile women (Bellver et al., 2008). Female reproductive system consists of interrelated structural elements: hypothalamus, pituitary gland, ovaries, other endocrine glands and target organs facilitating reproductive function. Thyroid gland is a chief part of the neuroendocrinal system; it significantly affects reproductive function. The hypothalamuspituitary-gonadal and hypothalamus-pituitary-thyroid systems are closely related due to the presence of common central regulating mechanisms. For example, the spread of thyroid gland dysfunction diagnosed at the examination in women, who seek clinical diagnosis and treatment of infertility, ranges from 2.5 to 38.3% (Lazarus & Premawardhana, 2005). In addition to gonadotropic hormones, ovarian function is determined by adrenal hormones produced under impact of ACTH. When a patient has developed any genetic defects in the enzyme systems, cortisol synthesis in adrenal glands decreases with the increase of level of ACTH followed by the increased production of androgens under normal synthesis. This condition may be typical of congenital adrenal hyperplasia. As a result of adrenal

hyperandrogenism, the suppression of ovarian function takes place, which leads to the development of a number of disorders in the menstrual cycle accompanied by anovulation.

The Means of Progress in Improving the Results of *in vitro* Fertilization Based on the Identification and Correction of the Pathology of Hemostasis 81

According to our conceptions, thrombophilia should be detected in case of everpresent thrombosis risk factors (thromboses) or miscarriage syndrome in the individual medical history. In order to prove it, we note the fact that, according to the guidelines of the International Society on Thrombosis and Haemostasis (ISTH), diagnosis of antiphospholipid syndrome (APS) shall be considered invalid unless at least one or more clinical implications of this pathology match the results of special laboratory assays (lupus anticoagulant effects,

Some publications indicate data on typical changes in the system of hemostasis that occurs during the IVF cycle. In particular, demonstration has shown that hormonal stimulation of the ovaries is accompanied by the increased von Willebrand factor, factors V and VIII, fibrinogen, enhanced APC resistance, and the decreased activity of principal physiological anticoagulants - antithrombin, proteins C and S (Andersson, 1997; Biron et al., 1997; Chan & Dixon, 2008; Curvers et al., 2001b; Nelson, 2009). Relationship between the predisposition to intravascular coagulation (thrombophilia) and unsuccessful ART results is actively discussed in current publications; however, mechanisms to produce the impact that increases thrombotic readiness on IVF are not absolutely clear. It is reported that women with thrombophilia may have increased risks for spontaneous abortion, preclinical pregnancy loss and recurrent implantation failure (Christiansen et al., 2006; Coulam et al., 2006b; Curnow et al., 2006; Many et al., 2001; Seghatchian et al., 1996; Stern & Chamley, 2006; Urman et al., 2005; Wichers et al., 2009; Younis et al., 2000). Presently, most studied and prevalent thrombophilias include APS and such risk factors as hereditary antithrombin III deficiency, factor V Leiden mutation, prothrombin mutation, polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene, plasminogen activator inhibitor-1 (PAI-1), fibrinogen, platelet glycoproteins ITGA2, ITGB3, and some others. Beer and Kwak (2000) treated unsuccessful IVF programs as the evident indication for assays capable of detecting hereditary and acquired thrombophilias. In 2004, Azem et al. (2004) demonstrated higher occurrence of hereditary thrombophilia in women with multiple IVF failures as compared to the group of fertile women who became pregnant after the first IVF cycle. In the research conducted by Qublan et al. (2006), 69% of women with recurrent IVF failures had at least one hereditary or acquired thrombogenic risk factor as compared to 25% of women in the group where this reproductive technology was successful. In the publication presented by Grandone et al. (2001), factor V Leiden mutation prevailed (14.4%) in women with recurrent IVF failures as compared to the controls (1%). Recently, Coulam and Jeyendran (2009b) have shown that frequency of genetic polymorphisms has been 1.6 times higher in infertile women with IVF failures as compared to the fertile group; thus, polymorphism of the MTHFR gene has prevailed. It has been also noted that the connection of thrombogenic risk factors with recurrent miscarriages and repeated implantation failures after IVF is mainly evident in the simultaneous carriage of several thrombogenic mutations

Mechanisms of hemostasis and implantation pathologies typical of some thrombophilias

antiphospholipid antibodies in the diagnostic titer) (Harris & Pierangeli, 2008).

and polymorphisms (Coulam et al., 2006b).

(carriage of thrombogenic risk factors):

*Diminished endometrial receptivity.* After high-quality embryos have been transferred into the uterine cavity and all evident causes for the failure of the IVF program have been eliminated, the unsuccessful IVF cycle is regarded as a result of disorders that occurred during the embryo implantation stage. A few years ago a new term - "repeated implantation failure" - was introduced (Margalioth et al., 2006; Tan et al., 2005). Recent years have shown that, despite the selection of obviously normal embryos for the transfer, only 20% of human embryos transferred in IVF cycles have been implanted in the uterus (International Committee for Monitoring Assisted Reproductive Technology (ICMART), 2002; Nyboe Andersen et al., 2009). This condition is considered to be based on the endometrial dysfunction occurring on the mollecular-cellular level. Lately, as a result of the tendency to transfer one or two embryos inside of an uterus, the method to determine repeated implantation failure has been modified. Margalioth et al. (2006) concluded that detailed examination should be done after 3 unsuccessful IVF cycles. Thus, the main causes are the factors which diminish endometrial receptivity: anatomical defects in the uterus, chronic endometritis, non-correspondence between the endometrial thickness and the day of embryo transfer, combined gynecologic pathology (adenomyosis, uterine fibroid), somatic diseases (including autoimmune diseases), and thrombophilias (Margalioth et al., 2006; Tan et al., 2005).

*Quantity of transferred embryos.* Due to the absence of conventional clinical guidelines for the treatment of infertility with the IVF method, there are on-going discussions regarding the elective transfer of one embryo to patients under 40. In 2009, a mathematical model was drawn to prove that the transfer of only one embryo shall decrease the pregnancy rate by 20% (Gelbaya et al., 2009).

*Embryo transfer on the stages of cleavage or blastocyst.* The data obtained during the systematic review and meta-analysis (Papanikolaou et al., 2008) of 1654 patients (blastocyst transferred to 815 patients, cleaving embryo transferred to 839 patients) showed that live birth rate was higher with embryos transferred on the blastocyst stage as compared to the rate at the cleavage stage. Multiple gestation rates were the same for both study groups.
