Follicular factors, serum estradiol, and outcome of pregnancy following in vitro fertilization and embryo transfer

Reproductive performance of donor mares subsequent to eFSH treatment in early vernal transition: Comparison between the first, second, and mid-season estrous cycles of the breeding season

The objective was to compare the reproductive performances associated with the first (Cycle-1), second (Cycle-2), and mid-season (MS-Cycle) ovulations of the breeding season in donor mares that were treated with equine-FSH (eFSH) in the early vernal transition. Mares (n=15) kept under ambient light were examined ultrasonographically per-rectum starting January 30. When an ovarian follicle > or =25mm in diameter was detected, twice daily eFSH treatments were initiated. The eFSH treatments ceased when a follicle > or =35mm was detected, and 36h later hCG was administered. Thereafter, mares were artificially inseminated every 48h until ovulation (Day 0). Trans-cervical embryo recovery attempts were performed on Day 8, and subsequently PGF2alpha was administered. Equine FSH was not administered in the subsequent estrous cycles. In Cycle-2 and in the MS-Cycle, hCG was administered when a follicle > or =35mm was detected; breeding, embryo recovery, and PGF2alpha administration, were similar to Cycle-1. Mares had an untreated estrous cycle (no treatment or breeding) between Cycle-2 and the MS-Cycle. All mares developed follicle(s) > or =35mm after 4.9+/-0.6 days of eFSH treatment, and subsequently ovulations occurred; mean (95% CI) interval from treatment initiation to ovulation was 7.9 (6.5-9.3) days. The number of preovulatory follicles (> or =30mm) at the time of hCG administration (Cycle-1: 2.2+/-0.3 compared with Cycle-2: 1.0+/-0 compared with MS-Cycle: 1.1+/-0.1 follicles), and the number of ovulations (2.5+/-0.4 compared with 1.0+/-0 compared with 1.1+/-0.1 ovulations) were greater (p<0.05) in Cycle-1. Nevertheless, mean embryo numbers did not differ among cycles (0.8+/-0.2 compared with 0.5+/-0.1 compared with 0.5+/-0.1 embryo/mare). On average, embryo morphology grade was less (p<0.05) in Cycle-1 as compared to non-eFSH cycles (combined Cycle-2 and MS-Cycle). This impaired embryo quality could be due to a seasonal effect, or negative effect of the eFSH treatment, which was possibly related to alterations in the hormonal environment (estradiol-17beta and progesterone). A prolonged IOI (>21 days) was recorded in 7 of 15 mares following the Cycle-1 ovulation, but not subsequently. In conclusion, eFSH treatment of vernal transitional donor mares stimulated ovulation within only few days of treatment, and the following embryo recovery rate was at least as good as in the subsequent estrous cycles; however, on average, embryos were morphologically impaired. In subsequent estrous cycles in the breeding season, ovulations, embryo recovery rates, and embryo variables did not appear to be negatively affected; however, the first inter-ovulatory interval of the breeding season was prolonged in approximately half of the mares.

Embryo associated immunosuppressor factor (EASF) and serum estradiol synergism in pre-embryonic development after in vitro fertilization

The aim of this study was to test whether the level of serum immunosuppressor factor (EASF) and serum estradiol (E2) play a cooperative role in the pre-implantation early embryonic development in IVF-patients. Serum samples were collected from 80 patients undergoing IVF-ET and the level of EASF in patient's sera was assayed using a two-site sandwich enzyme linked immunosorbent assay (ELISA) system. Two-hundred fifty-one IVF-culture media were obtained from these patients and the EASF activity was measured using concanavalin A-induced lymphocyte proliferation assay. EASF activity in embryo growth media, quality of ova, number of cells in each pre-embryo at the time of embryo transfer, cycle day 3 serum E2 and peak E2 levels were correlated with pregnancy outcome. Thirty-three out of 80 patients had detectable levels of serum EASF. The number of pre-embryos with > 4 cell stage at the time of embryo transfer correlated with the total number of ova retrieved in patients positive for serum EASF (P = 0.01) and patients that had an ongoing pregnancy at 7-8 weeks (P < 0.01). Ratio of the number of pre-embryos with > 4 cell stage at the time of embryo transfer and total number of ova retrieved correlated with cycle day 3 serum E2 (P < 0.01) and peak E2 (P = 0.01) levels only in patients positive for EASF. The EASF activity of embryo growth media correlated with cycle day 3 serum E2 (P = 0.0001) and peak E2 (P = 0.007) levels only in patients that were positive for EASF and got pregnant after IVF-ET. This study suggests that the levels of serum EASF and E2 may act synergistically in the development of early embryo.

Estrogen biosynthesis--regulation, action, remote effects, and value of monitoring in ovarian stimulation cycles

OBJECTIVE

To review current knowledge regarding estrogen biosynthesis, its regulation and action, specifically concerning local as opposed to remote effects of this hormone, and to examine the effectiveness and prognostic value of monitoring hormone concentrations and endometrial response in cycles of controlled ovarian hyperstimulation.

DATA IDENTIFICATION AND SELECTION

Studied that relate specifically to estrogen biosynthesis, enzymatic pathways, estrogen receptor physiology, and the clinical aspects of estrogen monitoring were identified through literature and Medline searches.

RESULTS

Folliculogenesis is the basic unit of ovarian activity, which has a dual purpose: oocyte maturation and steroid production. Steroidogenic granulosa and theca cells cooperate under gonadotropin control to produced estrogens by stimulating synthesis of steroidogenic enzyme messenger RNAs. Steroid synthesis is amplified further by local growth factors and follicular cell multiplication. Estrogen synthesis is directed by FSH, and only small amounts of LH are needed to amplify the follicular estrogenic potential. However, the growth of preovulatory follicles can proceed without LH, under FSH regulation only, even in the presence of low peripheral estrogen levels. Oocyte maturation and fertilization may proceed independently of ambient estrogen levels, leading to the assumption that estrogen exerts a minimal autocrine-paracrine function. The notable effect of follicular estrogen production is to promote adequate receptive endometrium for embryo implantation. Clinical treatment cycles may be monitored more effectively by evaluating end-organ response to estrogen rather than by evaluating absolute serum E2 concentrations or sonographic follicular measurements.

CONCLUSION

Follicular estrogen production is regulated by a complex set of signals that synergize to produce optimal steroidogenesis. Most importantly, the effect of estrogen is truly an endocrine effect, as it prepares the endometrium for implantation. Therefore, the goal of effective treatment and monitoring strategies should focus on direct assessment of the biologic activity of estrogen as it optimizes endometrial receptivity in anticipation of subsequent implantation.

Number of follicles, oocytes and embryos in human in vitro fertilization is relative to serum estradiol and progesterone patterns during different types of ovarian hyperstimulation

Preovulatory serum estradiol and progesterone levels as well as their ratio were compared in different types of ovulation induction in order to determine whether these findings could be used to predict the number of preovulatory follicles, number of oocytes aspirated and embryos obtained. Significantly more oocytes were retrieved by follicular aspiration and significantly more embryos developed in patients receiving gonadotropin-releasing hormone agonist and human menopausal gonadotropins than in those given other ovulation inductors. On days -2 and -1 of the cycle, serum estradiol levels were significantly lower in pure follicle-stimulating hormone induction. Serum progesterone was significantly higher in pure follicle-stimulating hormone cycles on days -4 and -3. In clomiphene citrate and human menopausal gonadotropin induction, progesterone levels were significantly lower on days -2 and -1, and on the day of follicular aspiration. Ratios of estradiol/progesterone were lower in pure follicle-stimulating hormone group from day -3 to day -1 of the cycle. A significant correlation was found between estradiol and progesterone serum levels and the numbers of preovulatory follicles, oocytes and embryos. The study revealed the usefulness of serum estradiol and progesterone determinations in assisted reproduction.

Psychogenic pregnancy disruptions in mammals

Evidence scattered over the literatures of zoology, psychology, agricultural science, and medicine indicates that diverse stressors will interfere with pregnancy in its early stages. It is probable that the most sensitive period is around the point of intrauterine implantation of fertilized ova. Although there is some indication that conventional "stress" hormones of the pituitary-adrenal axis can inhibit implantation, this evidence is too weak and inconsistent to suggest that these hormones are primary mediators of early pregnancy disruptions. Increasingly, evidence indicates that the balance of ovarian steroids is most important for pregnancy maintenance. It is well known that minute amounts of exogenous estrogens can completely disrupt pregnancy, and some new evidence suggests that endogenous estrogens may be released from the adrenals and/or ovaries during psychological stress.

Embryo associated immunosuppressor factor(s) secreted by preembryo and serum estradiol levels are predictive of pregnancy outcome: effect of gonadotropin releasing hormone agonist (GnRHa) treatment of patients undergoing in vitro fertilization and embryo transfer (IVF-ET)

The aim of the present study was to determine whether (i) the secretion of embryo associated immunosuppressor factor (EASF) by preimplantation embryo and serum estradiol (E2) play a cooperative role in pregnancy outcome and (ii) whether this association was affected by gonadotropin releasing hormone agonist (GnRHa) pretreatment of IVF-patients for ovarian stimulation. EASF activity was measured using concanavalin A-induced lymphocyte proliferation assay in 251 IVF-culture media obtained from 59 patients undergoing IVF-ET. EASF activity in embryo growth media, cycle day 3 serum E2 level and peak E2 levels were correlated with pregnancy outcome. Results indicate that in GnRHa non-treated patients (i) the immunosuppressive activity of embryo growth media significantly (p less than 0.05) differed between the patients with varying concentration of day 3 serum E2, (ii) the presence of immunosuppressive activity in the embryo growth media was associated with success of pregnancy in patients with day 3 serum E2 level of 21-40 pg/ml (p less than 0.005) and in patients with peak E2 level in serum of less than = 1500 pg/ml (p less than 0.05). No association in immunosuppressive activity, serum E2 level and successful pregnancy was seen in GnRHa treated patients. This preliminary study suggests that the concentration of serum hormones and factors that are altered due to GnRHa pretreatment of IVF-patients may affect the cooperative role played by EASF, E2 and other factors in the success of pregnancy.

Cryopreserved zygotes and embryos and endocrinologic factors in the replacement cycle

Several parameters relating to features of replacement cycles in 88 patients were found to influence implantation of cryopreserved zygotes and early cleaved embryos. Cryopreserved embryos were replaced in 47 patients with a natural cycle, resulting in 12 (25%) clinical pregnancies. Patients who had anovulation or irregular cycles received either 50 mg clomiphene citrate on days 5 to 9 or 100 mg on days 2 to 6; the incidence of clinical pregnancy was 7 of 23 (30%) and 2 of 18 (11%), respectively. Neither a rise in follicular phase estradiol (E2) nor absolute levels of E2 predicted implantation. The length of the follicular phase during the replacement cycle correlated well with previous menstrual cycles in 43 (54%) of the patients, and 16 (37%) of these patients became pregnant. The follicular phase was either longer or shorter than anticipated in 39 patients, and only 5 (13%) became pregnant: a detrimental effect was especially apparent when the follicular phase was shortened.