2,184 research outputs found
Impact of ovarian hyperstimulation on the luteal phase
No full textThe contemporary approach to ovarian stimulation in IVF treatment results in supraphysiological concentrations of progesterone and oestrogen in the luteal phase. These sex steroids act directly and indirectly to mature the endometrium, thus influencing its receptivity to implantation. The development of endometrial receptivity is a complex process that may be altered by inappropriate exposure to sex steroids. Alterations in the oestrogen to progesterone ratio, growth factor concentrations and cell adhesion molecule profiles may occur after ovarian stimulation, potentially affecting the receptivity of the endometrium. Recent clinical IVF studies have shown that implantation rates and corpus luteum function are influenced by oestrogen concentrations during the early luteal phase. Few comparative studies have been performed, but after ovarian stimulation there is a reduced implantation rate and a higher pregnancy loss rate before pregnancies can be detected clinically compared with natural cycle conceptions. Novel approaches to ovarian stimulation aimed at achieving a more physiological luteal phase endocrinology are now being developed. Data from a recent pilot study by our laboratory, involving minimal ovarian hyperstimulation and no luteal phase support, are discussed
Follicle development during the normal menstrual cycle
No full textAn understanding of the factors which determine initiation of follicle growth, recruitment and dominant follicle selection may increase our understanding of the underlying process of ovarian aging. In this article, these aspects of the normal menstrual cycle are reviewed. The morphological and endocrinological development in the early follicle is described from the primordial follicle stage. The degree of follicle-stimulating hormone (FSH) dependency is discussed, as is the relationship of estradiol (E2) production to follicle diameter. The principles governing mono-follicular selection are outlined, and the FSH 'threshold' and 'window' concepts are highlighted. Maximum FSH levels in the early follicular phase are shown to be variable between individuals. The relevance of this and the means by which individual sensitivity to FSH may be altered at the ovary in the context of ovarian aging are discussed
A pilot study involving minimal ovarian stimulation for in vitro fertilization: extending the "follicle-stimulating hormone window" combined with the gonadotropin-releasing hormone antagonist cetrorelix
No full textObjective: To study whether minimal interference in the process of selection of the single dominant follicle may serve as the basis for a simplified ovarian stimulation regimen for IVF. Design: Single-center randomized pilot study. Setting: Tertiary referral fertility center. Patient(s): Fifteen normo-ovulatory patients with a regular indication for IVF. Intervention(s): Ovarian stimulation for IVF was begun with 100 or 150 IU/d recombinant FSH starting on cycle day 5. From cycle day 8 or later, cotreatment was begun with 0.25 mg/d GnRH antagonist. No luteal support was provided. Main Outcome Measure(s): Total number of dominant follicles and characteristics of the endocrine cycle. Result(s): Multiple follicle development occurred in five of eight patients in the 100-IU group and in all seven women in the 150-IU group. Follicular phase and luteal phase lengths were normal, but the endocrine profile was abnormal. Conclusion(s): A fixed daily dose of 150 IU recombinant FSH starting in the midfollicular phase resulted in ongoing growth of a restricted number of dominant follicles and sufficient oocytes retrieved to lead to ET. A marked reduction in the total amount of gonadotropins administered compared with standard treatment was achieved. Withholding luteal support did not exclude pregnancies
Gonadotrophin-releasing hormone antagonists: application in ovary-stimulating and sex-steroid dependent disorders
No full textThe hypothalamic gonadotrophin-releasing hormone (GnRH) stimulates synthesis and secretion of luteinizing hormone (LH) and follicle stimulating hormone (FSH) by the gonadotrophic cells of the pituitary. The mechanisms of action of GnRH antagonists and of agonists is completely different. Due tot competitive blockage of GnRH receptors by antagonist administration, LH (and to a lesser extent FSH) levels drop rapidly. Moreover pituitary function normalizes immediately following cessation of medication. The direct and rapid action of GnRH antagonists, the dose dependent suppression of LH and FSH and the rapid restoration of hypophyseal function after cessation of the use of antagonists may shorten and simplify in-vitro fertilization, with less chance of side effects or complications. Further studies are required to decide whether antagonists can usefully be applied for other gynecological indications such as the polycystic ovary syndrome. The possibilities of profitable long term treatment will increase considerably if it proves possible to develop a sustained action formulation
FSH response-dose can be predicted in ovulation induction for normogonadotropic anovulatory infertility
No full textThe patient group with the best step-down profile for ovulation induction exhibited the closest match between the clinically applied and calculated starting dose of gonadotropins. Therefore, this study provides support for the concept that the individual effective FSH starting dose for gonadotropin induction of ovulation in anovulatory infertile patients can be predicted on the basis of initial screening characteristics, such as body mass index, clomiphene resistance or failure, free IGF-I and FSH. This may result in more effective patient treatment protocols, reduced complication rates and health-economic benefits
Pregnancy at a later age with the help of oocyte donation
No full textAn increasing number of women are delaying childbirth until an age when their fertility has significantly declined. Oocyte donation provides the opportunity for women to successfully conceive regardless of age. In The Netherlands, in 1997 the age limit for oocyte donation treatment was set at 45 years. The most important objections to pregnancy in older women are the medical risks for mother and child, the application of fertility treatments beyond the natural reproductive age and the psychosocial consequences for the child. However, based on international experience and recent data concerning the risks of pregnancy after oocyte donation in older women, it is proposed to increase the maximum age limit for this procedure to 50 years
Comparison of the phenotype of Chinese versus Dutch Caucasian women presenting with polycystic ovary syndrome and oligo/amenorrhoea
No full textBACKGROUND Polycystic ovary syndrome (PCOS) is a complex disorder with variable prevalence and clinical presentation in different populations, which may be mediated by geographical and ethnic background.METHODS We performed a comparison of phenotypic characteristics between 547 Chinese and 427 Dutch women with PCOS and oligo/amenorrhoea attending University Reproductive Centers in China and the Netherlands. RESULTS Chinese women presenting with a clinical diagnosis of PCOS were observed to have a higher incidence of hyperandrogenism (HA) (P < 0.001) and amenorrhoea (P < 0.001) compared with Dutch women, but no difference was observed in the incidence of polycystic ovaries (PCOs). Using population-specific cut-off values, Chinese women with PCOS demonstrated a higher incidence of increased BMI (P < 0.001), waist circumference (WC) (P < 0.001) and waist–hip ratio (P < 0.001) than Dutch women. In both groups, HA was associated with increased age, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and serum LH while PCOs correlated with BMI, WC, HOMA-IR, fasting insulin and elevated total testosterone. Associations specific for ethnic background were found between LH and HA, and between both BMI and HOMA-IR, and PCOs. CONCLUSIONS Reproductive and metabolic characteristics differed between the two ethnic groups. Chinese women were found to present more frequently with a phenotype associated with increased risk of metabolic complications later in life, compared with Dutch Caucasian women. Ethnicity seems to determine part of the specific phenotypical presentation of PCOS
- …
