Ultrastructure of human mature oocytes after slow cooling cryopreservation with ethylene glycol.

The morphological characteristics of frozen-thawed human mature oocytes (n = 12) were studied by light and transmission electron microscopy following cryopreservation using a slow cooling protocol including increasing concentrations of ethylene glycol (0.5-1.5 mol/l) and sucrose 0.2 mol/l in the freezing solution. Fresh human mature oocytes (n = 12) were used as controls. Fresh and frozen-thawed oocytes appeared rounded in section, with a homogeneous cytoplasm, an intact oolemma and a continuous zona pellucida. Disorganization of mitochondria-smooth endoplasmic reticulum aggregates and a decreased complement of microvilli and cortical granules were frequently observable in frozen-thawed oocytes. Increased density of the inner zona pellucida, possibly related to the occurrence of zona 'hardening', was sometimes found associated with a reduced amount of cortical granules. In addition, delamination of the zona pellucida was evident in some frozen-thawed samples. Finally, numerous vacuoles and secondary lysosomes were detected in the ooplasm of most frozen-thawed oocytes. In conclusion, frozen-thawed oocytes treated with ethylene glycol may show a variety of ultrastructural alterations, possibly related, at least in part, to the use of this cryoprotectant. Thus, the ethylene glycol-based protocol of slow cooling herein described does not seem to offer significant advantages in terms of oocyte structural preservation.

Permeability of human oocytes to ethylene glycol and their survival and spindle configurations after slow cooling cryopreservation.

BACKGROUND: To develop novel cryopreservation methods, we estimated the permeability coefficients Lp (hydraulic conductivity) and P(EG) (cryoprotectant permeability) of mature human oocytes after exposure to ethylene glycol (EG) and tested the efficiency of a multi-step slow cooling protocol based on this cryoprotectant. METHODS: Oocytes were perfused with 1.5 mol/l EG for 10 min. Oocyte volume at each time point was calculated and normalized to the original volume. Slow cooling was conducted by exposing oocytes to increasing EG concentrations (0.5, 1.0 and 1.5 mol/l n = 155) or 1.5 mol/l of propane-1,2-diol (PrOH) n = 102. Oocytes which survived cryopreservation n = 80 and fresh oocytes n = 73 were prepared for confocal microscopy analysis of the meiotic spindle. RESULTS: During EG exposure, oocytes underwent an abrupt 50% volume reduction. Complete recovery of the initial volume was not observed. From the values of a best fit plot, the coefficients Lp = 0.82 +/- 0.29 microm min(-1) atm(-1) (mean +/- SD) and P(EG) 0.10 +/- 0.01 microm s(-1) were generated. Survival rates after freezing with EG were lower than with PrOH (51.6 versus 71.5%, respectively, P < 0.05). The frequencies of normal spindle configuration were lower in frozen EG and frozen PrOH oocytes compared with fresh oocytes (53.8, 50.9 and 66.7%, respectively, P < 0.05). CONCLUSIONS: The oocyte plasmalemma possesses limited permeability to EG and EG exposure causes considerable osmotic stress. However, post-thaw rates of survival and normal meiotic spindle organization may be preserved by protocols which are designed in order to minimize osmotic stress.

Differential sucrose concentration during dehydration (0.2 mol/l) and rehydration (0.3 mol/l) increases the implantation rate of frozen human oocytes.

Novel protocols have increased survival and fertilization rates of cryopreserved oocytes. Nevertheless, in most cases clinical experiences have been disappointing or contradictory. Human oocytes of 141 patients were cryopreserved using a modified slow-cooling protocol involving 1.5 mol/l propane-1,2-diol (PrOH) and 0.2 mol/l sucrose during dehydration, while rehydration was conducted applying decreasing concentrations of PrOH and 0.3 mol/l sucrose. One thousand and eighty-three oocytes were frozen and 403 were thawed, with a survival rate of 75.9%. Among the 306 surviving oocytes, 252 were microinjected and 192 (76.2%) showed two pronuclei. One hundred and eighty zygotes (93.8%) cleaved. The proportion of good quality embryos (grade I and II) was 86.2%. All embryos were transferred and 17 clinical pregnancies were obtained. Pregnancy rates were 21.3% per transfer, 21.8% per patient, and 18.9% per thawing cycle. The implantation rate was 13.5% while the miscarriage rate was 11.8%. To date, four babies have been delivered, while the remaining pregnancies are ongoing. Increased oocyte survival rates can be achieved by moderately high sucrose concentrations in the freezing and thawing solutions. This also ensures elevated success rates in terms of fertilization, embryo development and clinical outcome.

Ultrastructure of human mature oocytes after slow cooling cryopreservation using different sucrose concentrations.

BACKGROUND: We studied the ultrastructural characteristics of human mature oocytes frozen/thawed (F/T) using different concentrations of sucrose. Fresh human mature oocytes were used as controls. METHODS: The oocytes (n = 48) were fixed in 1.5% glutaraldehyde at sampling (n = 16) or after freeze/thawing performed using a slow cooling method with propane-1,2-diol 1.5 mol/l and sucrose at either 0.1 mol/l (n = 16) or 0.3 mol/l (n = 16) in the freezing solution. The oocytes were then processed for electron microscopy observations. RESULTS: Fresh and F/T oocytes belonging to both study groups were regularly rounded in sections, with a homogeneous cytoplasm and an intact zona pellucida (ZP). Organelles (mainly mitochondria-smooth endoplasmic reticulum aggregates and mitochondria-vesicle complexes) were abundant and uniformly dispersed in the ooplasm. The amount and density of cortical granules appeared to be abnormally reduced in some F/T samples, independently of the sucrose concentration in the freezing solution: this feature was frequently associated with an increased density of the inner ZP, possibly related to the occurrence of zona 'hardening'. Furthermore, slight to moderate microvacuolization was revealed in the ooplasm of some F/T oocytes, particularly in those treated with sucrose 0.3 mol/l. CONCLUSIONS: Freeze/thawing procedures are associated with ultrastructural alterations in specific oocyte microdomains, presumably linked to the reduced developmental potential of mature cryopreserved oocytes. Further work is needed to determine whether or not a high concentration of sucrose plays a role, at least in part, in producing the above alterations.

Sperm DNA fragmentation: paternal effect on early post-implantation embryo development in ART.

BACKGROUND: The relationship between early embryo post-implantation development in couples undergoing assisted reproductive techniques (ARTs) and sperm chromatin alterations has not been satisfactorily explained. The aim of this study was to assess the relationship between sperm DNA fragmentation in IVF/ICSI patients, sperm parameters (concentration, motility and morphology) and ART outcome, especially with regard to clinical pregnancy and pregnancy loss (spontaneous miscarriage or biochemical pregnancy). METHODS: DNA fragmentation was evaluated by TUNEL assay, performed on sperm suspensions after density gradient separation, in 132 men undergoing an ART cycle (82 IVF and 50 ICSI) and correlated with sperm parameters and ART outcome. RESULTS: A highly significant negative correlation was found between DNA fragmentation and sperm parameters. There was a close relationship between DNA fragmentation and post-implantation development in ICSI patients: the clinical pregnancy and pregnancy loss rates significantly differed between patients with high and low sperm DNA fragmentation (P = 0.007 and P = 0.009, respectively). CONCLUSIONS: Sperm DNA fragmentation seems to affect embryo post-implantation development in ICSI procedures: high sperm DNA fragmentation can compromise 'embryo viability', resulting in pregnancy loss.

Clinical outcome of oocyte cryopreservation after slow cooling with a protocol utilizing a high sucrose concentration.

BACKGROUND: Recently, interest in oocyte cryopreservation has steadily increased. Newly developed protocols have dramatically improved survival rates, removing perhaps the major hurdle that has prevented this approach from becoming a fully established form of treatment. However, the clinical efficiency of these protocols has not been exhaustively explored and therefore remains controversial. METHODS: Morphologically normal oocytes displaying the first polar body were frozen-thawed with a slow cooling protocol that utilized 1.5 mol/l propane-1,2-diol (PrOH) and 0.3 mol/l sucrose. RESULTS: A total of 927 oocytes from 146 patients were frozen-thawed, achieving a 74.1% survival rate. Over 76% of microinjected oocytes displayed two pronuclei 16 h post-insemination, while the proportion of embryos at 44-46 h post-insemination was 90.2%. At this time point, the majority (68.3%) of embryos were at the two-cell stage, showing in most cases (78.7%) minimal or moderate fragmentation. Eighteen clinical pregnancies, three of which were twin, were observed, giving rise to rates of 12.3 and 9.7%, calculated per patient and per embryo transfer, respectively. The implantation rate was 5.2%. To date, four children have been born and three pregnancies resulted in spontaneous abortions, while the remaining pregnancies are ongoing. CONCLUSIONS: Our data indicate that although the combination of slow cooling and high sucrose concentration ensures high rates of oocyte survival, it is not sufficient to guarantee a high standard of clinical efficiency.

Criteria to assess human oocyte quality after cryopreservation.

Oocyte cryopreservation certainly represents one of the most attractive developments in the field of assisted reproduction, with the aim of preserving female fertility and circumventing the ethical and legal drawbacks associated with embryo freezing. Despite the achievement of the first pregnancy from frozen oocytes dating back as early as 1987, since then fewer than 150 pregnancies have been reported. Over a long period of time, application of oocyte storage on a large scale has been prevented by various factors, namely poor post-thaw survival. Fertilization rates remained low even after the introduction of intracytoplasmic sperm injection. Modifications of slow-freezing protocols, mainly based on the increase of the concentration of sucrose used as non-penetrating cryoprotectant (CPA) and the replacement of sodium with choline, appear to have decisively improved survival rates to over 80%. Investigations at the cellular level on thawed oocytes are largely lacking. Fertilization rates have also benefited from protocol modifications, reaching values indistinguishable from those normally obtained with fresh material. Vitrification protocols have also been tested, giving rise to improvements whose reproducibility is still uncertain. Data on the dynamics of fertilization and preimplantation development of embryos derived from frozen oocytes are extremely scarce. At the moment, clinical efficiency of oocyte cryopreservation cannot be precisely assessed because of the lack of controlled studies, although it appears to be considerably lower than that achieved with embryo freezing. In summary, encouraging advances have been made in the field of oocyte cryopreservation, but presently no protocol can ensure standards of success and safety comparable to those guaranteed by embryo storage.

Meiotic spindle imaging in human oocytes frozen with a slow freezing procedure involving high sucrose concentration.

BACKGROUND: One of the major concerns derived from the cryopreservation of meiotically mature oocytes is possible damage to the cytoskeletal apparatus, and in particular the meiotic spindle. METHODS: One hundred fresh oocytes showing the polar body I and high meiotic spindle birefringence (maximum retardance+/-1.5 mol/l SD = 2.58+/-0.1 nm), assessed through analysis, were included in this study. Oocytes were cryopreserved with a 1.5 mol/l 1,2-propanediol +0.3 mol/l sucrose solution. After thawing, spindles were imaged at 0, 3 and 5 h. Spindle birefringence was quantified by measuring microtubule maximum retardance. Signals of thawed oocytes were classified as absent (non-detectable), weak (1.55+/-0.3 nm) or high (2.50+/-0.2 nm). RESULTS: Immediately after thawing, only 22.9% of oocytes showed a weak birefringence signal, while only 1.2% of oocytes displayed a high signal. Three hours after thawing, the proportion of oocytes exhibiting a weak or high intensity signal was 49.4% and 18.1%, respectively. Finally, after culture for 5 h following thawing, a weak birefringence signal was detected in 51.8% of oocytes, while 24.1% showed a high signal. There was a statistically significant increase in signal restoration after 3 h of culture (P < 0.001). CONCLUSIONS: These results suggest that in mature oocytes stored via slow freezing, the meiotic spindle undergoes transient disappearance immediately after thawing but is reorganized in the majority of oocytes, at least to some extent, after 3-5 h of culture.

Volume changes of mature human oocytes on exposure to cryoprotectant solutions used in slow cooling procedures.

BACKGROUND: Despite the recent increase in pregnancies from cryopreserved human oocytes, success in terms of births per thawed oocyte is still poor. Modifications to cryopreservation protocols have not been based on measurement of the osmotic response of oocytes, and methodologies are often poorly described or protocols not strictly adhered to, inevitably resulting in variability. METHODS: Volume change of mature human oocytes was measured on exposure to cryoprotectant. Oocytes were exposed to either 0.75 mol/l propane-1,2-diol (PrOH) for 10 min; 1.5 mol/l PrOH for 10 min, having been exposed to 0.75 mol/l PrOH for 7.5 min; or 1.5 mol/l PrOH plus 0.2 or 0.3 mol/l sucrose for 10 min, having been exposed to 1.5 mol/l PrOH for 10 min. RESULTS: On exposure to PrOH alone, oocytes shrank and then re-expanded, having reached 75 and 84% of their starting volume in 0.75 and 1.5 mol/l, respectively. Oocytes shrank continuously in PrOH plus sucrose, reaching 67 or 55% of their initial volume in 0.2 or 0.3 mol/l sucrose, respectively. CONCLUSIONS: To improve consistency following cryopreservation, protocols must be strictly adhered to; small changes in duration of exposure to cryoprotectant can result in drastic changes in cellular hydration and thus the fate of the cell during freezing/thawing.

Mouse oocyte meiotic resumption and polar body extrusion in vitro are differentially influenced by FSH, epidermal growth factor and meiosis-activating sterol.

BACKGROUND: In this study, we compared the relative ability of FSH (100 mIU/ml), epidermal growth factor (EGF) (10 ng/ml), and follicular-fluid meiosis-activating sterol (FF-MAS, 10 micromol/l) to induce meiotic resumption and polar body I (PBI) extrusion in mouse oocytes. METHODS: Cumulus-enclosed oocytes (CEO) were co-incubated with meiosis-arresting agents, including 4 mmol/l hypoxanthine (Hx), 0.3 mmol/l dibutyryl cAMP (dbcAMP), and 8.5 micromol/l cilostamide, a selective inhibitor of the oocyte-specific phosphodiesterase 3 (PDE 3). RESULTS: In Hx-treated oocytes, FSH, EGF and FF-MAS induced meiosis resumption at very high rates, but only FSH and EGF also promoted PBI extrusion with high frequency. In experiments conducted in the presence of dbcAMP, FF-MAS was unable to promote an increase in germinal vesicle breakdown (GVBD) rate, whereas FSH and EGF generated a response similar to the Hx groups. Neither FSH, EGF nor FF-MAS caused any change in the meiotic status of CEO when meiotic arrest at the germinal vesicle (GV) stage was maintained by cilostamide. In the presence of Hx, naked oocytes (NkO) co-cultured with their cumulus cells were able to respond to the GVBD-inducing effect of FSH and EGF by resuming meiosis at high rate. CONCLUSIONS: Collectively, these results indicate that: (i) a signal triggered in cumulus cells by either FSH or EGF, but not necessarily coincident with FF-MAS, may contribute to meiotic maturation, supporting GVBD and extrusion of PBI; (ii) the transmission of this signal can occur in a paracrine fashion, at least with reference to the breakdown of the GV. It also appears that concomitant regulation of intra-oocyte cAMP degradation is a prerequisite for meiosis resumption.

Half-dose depot triptorelin in pituitary suppression for multiple ovarian stimulation in assisted reproduction technology: a randomized study.

BACKGROUND: Pituitary suppression by depot GnRH agonist may be excessive for ovarian stimulation in assisted reproduction technology. This study compares the efficacy of standard and half-dose depot triptorelin in a long protocol. METHODS: A total of 180 patients were randomized into two groups using sealed envelopes. Pituitary desensitization was obtained in group 1 (90 patients) with half-dose (1.87 mg) triptorelin depot in the mid-luteal phase of their menstrual cycle, and in group 2 (90 patients) with full-dose (3.75 mg) triptorelin. RESULTS: There was no premature LH surge, with LH levels being lower in the full-dose group (1.04+/-0.05 versus 0.7+/-0.06 IU/l on the day of hCG). The number of FSH ampoules used was lower in group 1 (42+/-2 versus 59+/-3). The numbers of mature oocytes (10.1+/-0.54 versus 7.4+/-0.55), of fertilized oocytes (8.24+/-0.35 versus 6.34+/-0.37) and of embryos (7.8+/-0.36 versus 5.9+/-0.37) were significantly higher in group 1. No significant differences were found in pregnancy (38.8 versus 25.3%), implantation (22.6 versus 13.8%) or abortion (6.1 versus 5.0%) rates. Cumulative pregnancy (fresh plus frozen embryo transfers: 56.8 versus 35.4%) rate was significantly higher in group 1. CONCLUSION: A half-dose of depot triptorelin can be successfully used in ovarian stimulation for IVF and produce a higher number of good quality embryos with a good chance of implantation.

Oocyte cryopreservation: a biological perspective.

Oocyte cryopreservation would amount to a major breakthrough in reproductive medicine. Diverse strategies have been tested to minimise cooling-induced cell injury. Nevertheless, oocytes from various species have shown a particular sensitivity to freezing, due to their unique biological characteristics. Storage of human mature oocytes with slow freezing has resulted in low survival rates, although recent studies based on modified methods have reported higher success. Survival after thawing is not necessarily a guarantee of unaltered viability. Developmental failure at pre- or postimplantation stages may originate from critical perturbations of various cell components, such as the chromosome segregation apparatus, the intracellular calcium signalling system, and the cytoskeleton. Germinal vesicle (GV)-stage oocytes have been suggested to be more amenable to freezing. But their use would require efficient in vitro maturation systems, which are not presently available. Oocyte cryopreservation remains a realistic objective, provided that more systematic approaches are applied, such as thorough analysis of the plasmalemma permeability to water and the diverse cryoprotectants.

GnRH analogs: depot versus short formulations.

Gonadotropin releasing hormone agonists (GnRH-a) are widely used in controlled ovarian hyperstimulation (COH) for assisted reproduction (ART). Two different formulations are now available: short formulations and depot formulation. Some authors have suggested that depot GnRH-a induce a too high pituitary suppression and have put forward protocols using reduced GnRH-a doses. A reduced dose of daily triptorelin is enough for pituitary suppression during ovarian stimulation but provides no significant improvement in IVF cycle outcome when compared with depot formulation in normally responding women. However, it seems to improve ovarian response and overall results in poor responding patients. Low doses of short GnRH-a allow shorter treatment, requiring lower amounts of gonadotropins. This possibility should be considered in view of its economic advantage.

Pelvic sonography and uterine artery color Doppler analysis in the diagnosis of female precocious puberty.

OBJECTIVES: To evaluate the role of ultrasound and color Doppler analyses in the diagnosis of precocious puberty. METHODS: Gray-scale sonographic uterine and ovarian evaluation together with color Doppler analysis of the uterine artery were prospectively performed in 29 girls presenting with premature breast development and pubic hair growth. The values were compared with results obtained from the gonodotrophin releasing hormone stimulation test. Excluded from the study were patients with isolated thelarche or isolated pubarche and those patients with gonodotrophin releasing hormone-independent puberty and with polycystic ovaries. RESULTS: According to the Tanner scale, all the girls presented a breast stage of 2-3 and pubic hair stage 2-3. The uterine size was greater in those girls who presented a pubertal response to the gonodotrophin releasing hormone test (Group II; n = 20) (8.07 +/- 4.47 mL) than in those who did not (Group I; n = 9) (3.07 +/- 1.18 mL; P = 0.001). The ovarian volume and the number of small follicles was not significantly different between the groups. On Doppler analysis, more elevated impedances were observed in Group I (pulsatility index = 3.28 +/- 0.37) than in Group II (pulsatility index = 2.29 +/- 0.19; P = 0.001) girls. The presence of a low pulsatility index (< 2.5) at the level of the uterine arteries had a high diagnostic value for precocious puberty (sensitivity 86%, specificity 100%). CONCLUSIONS: Uterine artery Doppler analysis may assist the diagnosis of gonodotrophin releasing hormone-dependent precocious puberty, may be useful for the selection of those girls needing treatment, and may simplify the follow-up of girls treated for precocities.

Endometriosis: absence of recurrence in patients after endometrial ablation.

BACKGROUND: The present study was undertaken to evaluate differences between patients with and without eutopic endometrium in the recurrence of ectopic endometriotic implants. METHODS: Endometrial ablation (EA) was carried out in 14 women out of 28 laparoscopically treated for endometriosis and recurrence of the disease was evaluated 24 months later. Data were compared using paired Student's t-test and chi2 test. RESULTS: Patients undergoing EA procedures did not exhibit recurrence of endometriosis while nine patients without that procedure had recurrence of the disease (P < 0.001). The endometrial cells found in the debris of the cul de sac of eight patients who did not undergo EA were both stromal and epithelial cells. No blood or blood cells were found in the cul de sac of patients undergoing EA. CONCLUSIONS: The present study supports a role of eutopic endometrium in the recurrence of endometriosis through tubal dissemination of endometrial debris and implantation of endometrial cells into the abdomen.

Uterine contractility: vaginal administration of the beta-adrenergic agonist, terbutaline. Evidence of direct vagina-to-uterus transport.

Spontaneous uterine contractility during the menstrual cycle is required for menstruation, gamete transport, and, most likely, embryo nidation. Abnormal uterine contractility has been linked to dysmenorrhea, a condition associated with painful uterine cramping. Based on previous studies with progesterone, we have postulated the existence of a portal system that is responsible for some degree of direct vagina-to-uterus transport of administered compounds (i.e., the "first uterine pass effect"). It is possible that treatment with uterorelaxing substances, particularly beta-adrenergic agonists, may alleviate the uterine discomfort that accompanies dysmenorrhea. However, side effects encountered with oral administration of beta-agonists limit their utility. Alternatively, vaginal delivery of beta-agonists could solve this dilemma by enhancing their efficacy and reducing side effects. Therefore, in the current study we used hysterectomy specimens and an in vitro uterine perfusion system to test the vagina-to-uterus transport of [3H]terbutaline, a well-known beta-agonist. With the use of autoradiographic and scintillation counting techniques, our results clearly show progressive diffusion of labeled terbutaline from the rim of vaginal tissue through the uterus during the first 12 hours of perfusion. This indicates that uterine targeting of terbutaline can be accomplished through vaginal administration, suggesting a new therapeutic modality in women's health care.

The embryo question.

In Italy, the seat of the Vatican, the problem of the "rights of the embryo" has been particularly felt and has caused bitter debate between laymen and clergy. The disagreement has focused primarily on the definition of "person," "individual," and the "beginning of life." Catholics, for the most part, have contested the concept of the "pre-embryo" and have tried to have a law passed that would impede the production and freezing of supernumerary embryos (according to the hypothesis of the "simple case"). In the same way, Catholics have strongly opposed the possible manipulation of embryos, including pre-implant genetic investigations. In addition to Catholic teachings, the National Committee for Bioethics has also declared itself favorable to the protection of the "waking life." It published a special document on the theme in a period in which the Committee was composed only of strict Catholics, following action taken by the then Prime Minister, Berlusconi, who believed it necessary to exclude and remove all lay members from the Committee. The document of the National Committee for Bioethics, which distinguishes itself for having declared that "the embryo is one of us," has been the cause of a transversal political aggregation that has gathered Catholic parliamentarians from different political parties and that has begun a campaign to acknowledge the prerogatives and rights of the embryo which Italian law attributes only to the baby after its birth. An intense debate continues on all these themes, and in back of all this is the warning from the Church to re-examine the Italian law dealing with the voluntary interruption of pregnancy.

Perifollicular vascularity and its relationship with oocyte maturity and IVF outcome.

New markers of embryo ability to implant are pursued continuously. Understanding whether an oocyte is really "mature," that is, ready to be fertilized, would be of great help in choosing an embryo that will implant. It is usual to pay attention to the phase of meiosis, considering the extrusion of the polar body (metaphase II) to be the only sign of the maturity of the oocytes. Nevertheless, understanding more about how the cytoplasm contributes to an oocyte's competency also shows promise as a method of predicting which embryos will implant. Some studies about perifollicular vascularity have demonstrated that embryos originating from oocytes developed in well-vascularized follicles have a higher implantation rate than those originating from oocytes developed in follicles with poor vascularization. Here, we report our results from a preliminary study in which embryos were transferred according to the degree of vascularization of the follicle. Women who received embryos originating from oocytes developed in well-vascularized follicles had a statistically higher pregnancy rate than women who received embryos deriving from oocytes grown in more poorly vascularized follicles (34% vs. 13.7%).

Effect of duration of estradiol replacement on the outcome of oocyte donation.

PURPOSE: To investigate if duration of estrogenic endometrial stimulation can affect recipient pregnancy rate in an ovum donation program. METHODS: Each recipient received micronized 17 beta-estradiol orally in a steadily increasing dosage from 2 to 6 mg daily over a period of time varying from 5 to 76 days until oocyte were available for donation. Recipients (520 patients for a total of 835 transfer cycles) were retrospectively divided into five groups depending on the duration of E2 administration. RESULTS: No significant difference was seen in pregnancy and implantation rates between groups. There was a higher number of miscarriages in Group A (41%), p < 0.05 vs. Group B (15%), and vs. Group E (1%). Age, number of pregnancies and miscarriages, or implantation rate in donors (327 women aged < 35 years) were similar in all the five groups. CONCLUSIONS: Endometrial receptivity is tolerant to a wide duration of E2 treatment (until 2 months), while waiting for oocytes available for donation, but best results are achieved with a treatment range of 11 to about 40 days.

Effect of reduced dose of triptorelin at the start of ovarian stimulation on the outcome of IVF: a randomized study.

BACKGROUND: Partial pituitary desensitization using gonadotrophin-releasing hormone (GnRH) agonists may be sufficient in women undergoing controlled ovarian hyperstimulation for assisted reproduction. However, the minimal effective agonist dose remains to be determined. The aim of the study was to investigate the effect of a reduced daily dose of triptorelin, administered at the start of ovarian stimulation, on the results of IVF and intracytoplasmic sperm injection. METHODS: A total of 132 patients was randomized in two groups. Pituitary desensitization was obtained in group 1 (66 patients) with a single 3.75 mg injection (i.m.) of triptorelin. In group 2, 66 patients received 100 microg triptorelin daily, which was then reduced to 50 microg at the start of follicle-stimulating hormone (FSH) stimulation. RESULTS: No significant differences were found in terms of pregnancy rate per transfer (38% in group 1 versus 34.9% in group 2), implantation rate (20.2 versus 18%) and abortion rate (8.3 versus 9.1%). The number of FSH ampoules used, as well as the number of days stimulation required, was significantly reduced in group 2 (41 +/- 26 versus 46.6 +/- 25.3, P < 0.03 and 11 +/- 1.3 versus 11.8 +/- 1.5, P < 0.002 respectively). No significant differences were seen in oestradiol concentrations and in follicle number, in the quantity of oocytes collected and fertilized, or in the number of embryos obtained or transferred. CONCLUSION: A reduced dose of triptorelin is enough for pituitary suppression during ovarian stimulation but provides no significant improvement in IVF cycle outcome when compared with depot formulation. The possibility of a shorter treatment protocol requiring lower amounts of gonadotrophins should be considered in view of its economic advantage.