P-480 Oocyte survival and embryo viability rates are not affected by the transportation of vitrified donor oocytes: a sibling study with oocytes from the same cohort

Study question

Are oocyte survival and embryo viability rates impaired by the shipment of vitrified donor oocytes in nitrogen vapors from one country to another

Summary answer

Oocyte survival and embryo viability rates are not affected by their transportation in nitrogen vapors showing similar parameters in the clinics of origin and abroad.

What is known already

The demand for donor eggs increases as egg donation cycles rise in ART clinics. Due to the legislation in some countries and the lack of donors, clinics choose to import vitrified oocytes from egg banks. Vitrification is a well established technique and the effectiveness of egg banks with vitrified oocytes has been proven. However, the comparison of sibling oocytes from the same donor's cohort in origin and after transportation remains to be study

Study design, size, duration

This is a retrospective, multicentric, observational study

Participants/materials, setting, methods

A total of 1030 vitrified oocytes from 55 donors were split between recipients in two different countries. Three clinics, one in Argentina (clinic of origin) and two in Brasil (clinics of destination) participated in this study. A total of 717 oocytes remained in the clinic of origin and were used to perform IVF cycles, while 313 oocytes were shipped abroad to the clinics of destination. Oocytes were transported at -196ºC in tanks with nitrogen vapors.

Main results and the role of chance

No significant differences were observed for any of the parameters analyzed except for the blastocyst rate. The lower blastocyst rate observed for the clinics of destination could be explained by the fact that one of the clinics performed embryo transfers and cryopreservations on day 3 leaving only surplus embryos (with lower potential) to blastocyst culture. When analyzing the embryo utilization rate, defined as the total of embryos on day 3 or day 5 destined to transfer or cryopreservation, results were not statistically different between the clinic of origin and both clinics of destination.

Limitations, reasons for caution

This study only evaluated the performance of sibling oocytes between the clinic of origin and two clinics of destination. It may be necessary to expand the number of clinics to generalize that sibling oocytes have the same potential regardless if they are shipped or not.

Wider implications of the findings

This study supports the establishment of international donor egg banks to attend the demands of IVF centers around the world. The transportation of vitrified oocytes from one country to another is a safe procedure as demonstrated by similar embryo viability parameters derived from sibling vitrified donor oocytes.

Trial registration number

Not applicable

Fibroblast growth factor 2 (FGF2) is present in human spermatozoa and is related with sperm motility. The use of recombinant FGF2 to improve motile sperm recovery

Fibroblast growth factors (FGFs) and their receptors (FGFRs) regulate several functions of somatic cells. In a previous work, we reported FGFR expression in human spermatozoa and their involvement in motility. This study aimed to evaluate the presence and localization of fibroblast growth factor 2 (FGF2) in human spermatozoa, to determine the relationship of FGF2 levels with conventional semen parameters and to assess the effect of recombinant FGF2 (rFGF2) on sperm recovery in a selection procedure. Western immunoblotting analysis using an antibody against FGF2 revealed an 18-kDa band in sperm protein extracts. The protein was immunolocalized in the sperm flagellum and acrosomal region, as well as in all germ cells. Sperm FGF2 levels, assessed by flow cytometry, showed a positive (p < 0.05) correlation with sperm concentration, motility, total sperm number and total motile cells per ejaculate. Moreover, samples with abnormal motility depicted diminished (p < 0.01) FGF2 levels compared to those with normal motility. Spermatozoa exposed to rFGF2 bound the protein, exhibited higher (p < 0.05) total and motile sperm recoveries, and increased (p < 0.01) kinematic parameters after the swim-up. Findings herein presented lead to consider sperm FGF2 level as a potential marker of sperm quality, and rFGF2 as a supplement for improving sperm recovery in selection techniques.

Endocrinological and ultrasonographic variations after immature oocyte retrieval in a natural cycle

BACKGROUND

In-vitro oocyte maturation is an appealing alternative in reproductive medicine but the results obtained are still poor. The aim of our prospective and observational investigation was to study the hormonal modifications that immature follicular aspiration might induce in a natural cycle as well as the implications that these alterations may have in the endometrium.

METHODS

Eleven patients (13 cycles) were included in our in-vitro oocyte maturation programme. Ovaries were scanned with transvaginal probes every day and follicular aspiration was performed when a follicle of 9 mm was visualized. Blood was also drawn for hormonal analysis. Endometrial thickness was recorded every day after oocyte retrieval. Two endometrial biopsies were taken on days 6 and 8 after oocyte retrieval.

RESULTS

We observed a significant drop in serum oestradiol concentrations after immature oocyte retrieval previous to follicle dominance. Immediately after, rises in both FSH and LH were detected. Also, a new dominant follicle started to grow 3-4 days later. Steroid hormones secreted by this newly recruited follicle were significantly lower than in controls, inducing inadequate endometrial thickness.

CONCLUSIONS

These studies show that exogenous hormonal administration might be necessary to achieve a correct endometrial growth when in-vitro oocyte maturation is employed in IVF.

The potential use of maturation in vitro of human oocytes in low responder patients

PURPOSE

To assess whether maturation in vitro of human oocytes (MIVHO) could be an alternative treatment in low responders to ovarian stimulation for in vitro fertilization (IVF).

METHODS

Prospective case-control study. Spontaneously ovulatory women who volunteered were included in our program of MIVHO at the Instituto Valenciano de Infertilidad. Rates of oocyte retrieval, in vitro maturation, fertilization, and development up to the blastocyst stage were studied.

RESULTS

A significantly increased rate of oocyte retrieval was found when the pickup was performed before follicular selection. No differences were found when MIVHO was used in a low responder patient with an ovarian content of early antral follicles > 5 as compared to normal responders.

CONCLUSIONS

MIVHO could be a successful choice in low responder patients with an acceptable number of early antral follicles. Oocyte retrieval should be performed before follicular selection in order to obtain more oocytes.

Maturation in vitro of human oocytes from unstimulated cycles: selection of the optimal day for ovum retrieval based on follicular size

The potential use of immature oocytes for in-vitro fertilization (IVF) requires the conditions for successful maturation to be defined. This study focused on the day of oocyte retrieval. The selection of a dominant follicle may induce endocrine changes in the remaining cohort that may be detrimental to their subsequent fertilization and embryonic development. Natural cycles in volunteer donors were followed by measurement of serum oestradiol and by vaginal ultrasound, starting on day 3 of the cycle. Cycles were randomly allocated to one of two groups: group 1 (n = 10), in which follicles were aspirated before the leading follicle was 10 mm in diameter; and group 2 (n = 9), in which follicles were aspirated when a dominant follicle was clearly visible with diameter >10 mm. Oocytes were cultured in vitro to metaphase II (MII) stage, donated, and inseminated by intracytoplasmic sperm injection (ICSI) with husband's spermatozoa. Those that became fertilized within 24 h were further co-cultured in autologous endometrial epithelial cells up to the blastocyst stage, and cryopreserved. There was a significantly (P < 0.05) increased rate of oocyte retrieval in group 1 (70.8% of aspirated follicles) compared with group 2 (50.5%). Maturation to MII and fertilization were similar between the groups. However, development to blastocyst stage was significantly (P < 0.05) higher in group 1 embryos (56.5%) compared with group 2 (35.7%). There was a positive correlation (r2 = 0.1978) between the appearance of the cumulus cells and the ability to develop to blastocyst stage when both parameters were analysed in group 1, whereas no such correlation was found in group 2. In conclusion, our data suggest the importance of retrieving immature oocytes before follicular selection, and define the conditions for the first stage in the use of immature oocytes. Further stages must be defined before this technique can be used clinically.

Evaluation of the ovarian reserve in young low responders with normal basal levels of follicle-stimulating hormone using three-dimensional ultrasonography

OBJECTIVE

To assess the ovarian content of selectable (2-5 mm) follicles using three-dimensional ultrasonography in low responders to ovarian stimulation for IVF.

DESIGN

Prospective case-control study.

SETTING

IVF program at the Instituto Valenciano de Infertilidad.

PATIENT(S)

Ten low responders < or =35 years of age with normal basal serum FSH and eight control patients with normal response in a previous cycle.

INTERVENTION(S)

Blood was drawn under basal (day 3) conditions. Three-dimensional ultrasound was performed in both ovaries using a vaginal probe.

MAIN OUTCOME MEASURE(S)

Basal serum E2 and FSH measurements. The ovarian volume and the number of follicles > or =2 mm in each ovary were recorded and compared between the groups.

RESULT(S)

Low-responder women had significantly higher serum FSH levels than controls despite having FSH values within the normal range. The number of selectable follicles and the total number of follicles with an antrum were significantly decreased in low responders as compared with normal responders. Ovarian volume did not differ between the groups.

CONCLUSION(S)

This study introduces three-dimensional ultrasound as a novel method for the evaluation of low responders. The results show that the most plausible explanation for low response in young women with normal serum FSH is diminished ovarian reserve.

Ovarian follicular dynamics: from basic science to clinical practice

The management of low responders (LR) to ovarian stimulation in cycles of assisted reproduction (AR) is a difficult challenge. Aging of the ovary and LR are coincidental in many situations, but LR is also present in young patients undergoing AR. In fact, today it is a recognized cause of infertility. When the aged ovary is considered, there is evidence that the functioning of the granulosa cells as well as the quality of the oocytes and resulting embryos are affected. Similarly, in young LR, the production of inhibin is affected. However, there is no evidence that the quality of the oocyte and/or the resulting embryo is affected. In this study, we have retrospectively analyzed our files and observed that the quality of the oocytes and embryos was similar between younger and older LR and normal responders (NR). Studies using color Doppler vaginal ultrasound have shown that the pulsatility index (PI) and the resistance index (RI) were increased in LR as compared with NR, suggesting that there was some degree of vascular resistance to flow. Treatment of LR is also a difficult challenge. Ovum donation is a successful treatment for LR, since cumulative birth rates are > 85% with four attempts of embryo transfer. The future may be promising for LR once new technologies are introduced into clinical practice. The use of recombinant gonadotropins and genetically engineered human gonadotropin derivatives may be of considerable help for LR. Similarly, non-gonadotropin hormones, such as cytokines or growth factors, may be shown to play a role in the stimulation of the ovary in the near future, and may therefore open new frontiers for treatment of LR.

The use of long- and short-acting forms of gonadotrophin-releasing hormone analogues in women undergoing oocyte donation

Evidence accumulated in in-vitro fertilization (IVF) cycles suggests that the use of long-acting forms of gonadotrophin-releasing hormone analogues (GnRHa) for pituitary desensitization may impair the outcome of IVF as compared to classical short-acting formulations. Whether the negative effects are directed against the corpus luteum, the endometrium, or both is unknown. However, the presence of high affinity binding sites for gonadotrophin-releasing hormone (GnRH) in the human endometrium suggests a possible role of these analogues on this target organ, affecting embryo implantation. In the present study, we tested direct effects of two different forms of GnRHa on implantation using the ovum donation model. Patients were prospectively allocated to one of the three study groups: the short-acting form of the analogue leuprolide acetate (group I; n=64), the long-acting form of the same analogue (group II; n=58), and the long-acting preparation of the analogue tryptorelin (group III; n=61). A total of 68 cycles of embryo transfer was carried out in group I, whereas 67 were performed in group II and 65 in group III. Cancellation rates were respectively 18.1, 17.3 and 18.8% because of bleeding while being on the waiting list for anonymous oocyte donation. The number of oocytes donated, fertilization rates and embryos replaced in each group were similar. As a result, pregnancy rate per transfer was 38.2, 49.3 and 44.6% respectively. Implantation rates per embryo replaced were respectively 13.4, 19.1 and 17.0%. These data suggest that the use of a long-acting form of GnRHa provides success rates similar to the short-acting preparations, resulting in more convenient medication for patients with ovarian function included in ovum donation programmes.