P–464 What is the optimal ovarian stimulation (OS) protocol for women who undergo planned oocyte cryopreservation (POC)?

Study question

When repeated cycles of OS for planned oocyte cryopreservation using a standard GnRH antagonist protocol are required, can OS protocol modifications improve oocyte yield?

Summary answer

Compared to repeating a standard GnRH antagonist protocol, switching to a long GnRH agonist protocol for POC results in a higher number of cryopreserved oocytes.

What is known already

The total number of cryopreserved oocytes is a key parameter of POC programs because of its association with livebirth. A substantial proportion of women embarking on POC will undergo repeated cycles of OS to reach their desired target number of vitrified oocytes. According to recent guidelines, the GnRH antagonist protocol with GnRH agonist triggering is considered the first choice protocol for POC, because of its safety profile and convenience. However, in women with normal ovarian reserve, the long GnRH agonist protocol results in a higher number of oocytes retrieved. Evidence regarding the optimal protocol for POC is limited.

Study design, size, duration

This is a single-centre, retrospective cohort study including 283 women who had a first cycle for POC using a standard GnRH antagonist protocol and who requested a second OS cycle to increase their total number of vitrified oocytes for later use. The choice of protocol for the second cycle was left at the discretion of the reproductive medicine specialist. All OS cycles took place between January 2009 and December 2019 in a tertiary referral hospital.

Participants/materials, setting, methods

After ovarian reserve testing, the first cycle OS was performed using rFSH or HPhMG in a GnRH antagonist protocol. For the second cycle, a GnRH antagonist protocol with or without antagonist pretreatment, or a long GnRH agonist protocol was prescribed. The primary outcome was the number of mature oocytes (MII) vitrified per cycle. Cycle characteristics were compared. Data were assessed by generalized estimating equation (GEE) regression analysis adjusting for covariates.

Main results and the role of chance

In total, 226 (79.9%) women had a GnRH antagonist protocol and 57 (20.1%) had a long GnRH agonist protocol in their second OS cycle for POC. Overall, mean age was 36.6±2.4 years. The median (CI) number of mature oocytes vitrified after the second OS cycle was significantly higher than that after the first cycle [8 (5–11) vs. 7 (4–10), p < 0.001]. According to GEE multivariate regression, adjusting for relevant confounders, switching from a GnRH antagonist protocol in the first cycle to a long GnRH agonist protocol in the second cycle was the only significant predictor of the number of vitrified oocytes after the subsequent cycle (coefficient 1.59, CI 0.29–2.89, p-value = 0.017). Age, AFC, initial dose and type of gonadotropins did not predict the number of vitrified oocytes. None of the women developed moderate or severe OHSS.

Similarly, of 174 women who underwent their first OS cycle with a standard GnRH antagonist protocol, 133 women (76.4%) had the same protocol for their second cycle and 41 women (23.6%) an additional three-day course of GnRH antagonist pretreatment. According to GEE multivariate regression, this protocol modification did not result in more mature oocytes available for vitrification (coefficient –0.25, CI –1.86–1.36, p-value = 0.76).

Limitations, reasons for caution

These data should be interpreted with caution because of the retrospective design and limited sample. Although more oocytes were obtained with a long GnRH agonist protocol we have no data on livebirth in women returning to use their oocytes to support the choice for a specific OS protocol for POC.

Wider implications of the findings: Although oocyte yield in the context of POC is an important parameter that may be modulated by the choice of OS protocol, the ultimate outcome measure of a successful POC program is livebirth after oocyte vitrification. Future research of oocyte parameters reflecting oocyte quality is paramount.

Trial registration number

Not applicable

Combining fertility preservation procedures to spread the eggs across different baskets: a feasibility study

STUDY QUESTION

What is the reproductive potential following combinations of ovarian stimulation, IVM and ovarian tissue cryopreservation (OTC) in female patients seeking fertility preservation (FP)?

SUMMARY ANSWER

In selected patients, combining different FP procedures is a feasible approach and reproductive outcomes after FP in patients who return to attempt pregnancy are promising.

WHAT IS KNOWN ALREADY

FP is increasingly performed in fertility clinics but an algorithm to select the most suitable FP procedure according to patient characteristics and available timeframe is currently lacking. Vitrification of mature oocytes (OV) and OTC are most commonly performed, although in some clinical scenarios a combination of procedures including IVM, to spread the sources of gametes, may be considered in order to enhance reproductive options for the future.

STUDY DESIGN, SIZE, DURATION

Retrospective, observational study in a university-based, tertiary fertility centre involving all female patients who underwent urgent medical FP between January 2012 and December 2018. Descriptive analysis of various FP procedures, either stand-alone or combined, was performed, and reproductive outcomes of patients who attempted pregnancy in the follow-up period were recorded.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In total, 207 patients underwent medical FP. Patient-tailored strategies and procedures were selected after multidisciplinary discussion. When deemed feasible, FP procedures were combined to cryopreserve different types of reproductive tissue for future use. The main primary outcome measure was the number of mature oocytes. Live birth rates were evaluated in patients who returned for reproductive treatment.

MAIN RESULTS AND THE ROLE OF CHANCE

Among patients seeking FP, 95/207 (46%) had breast cancer, 43/207 (21%) had haematological malignancies and 31/207 (15%) had a gynaecological tumour. Mean ± SD age was 27.0 ± 8.3 years. Eighty-five (41.1%) patients underwent controlled ovarian stimulation (COS), resulting in 10.8 ± 7.1 metaphase II (MII) oocytes for vitrification. Eleven (5.3%) patients had multiple COS cycles. Transvaginal oocyte retrieval for IVM was performed in 17 (8.2%) patients, yielding 9.2 ± 10.1 MII oocytes. Thirty-four (16.4%) patients underwent OTC combined with IVM of oocytes retrieved from ovarian tissue 'ex vivo' (OTO-IVM), yielding 4.0 ± 4.3 MII oocytes in addition to ovarian fragments. Seventeen (8.2%) patients had OTC combined with OTO-IVM and transvaginal retrieval of oocytes for IVM from the contralateral ovary, resulting in 13.5 ± 9.7 MII oocytes. In 13 (6.3%) patients, OTC with OTO-IVM was followed by controlled stimulation of the contralateral ovary, yielding 11.3 ± 6.6 MII oocytes in total. During the timeframe of the study, 31/207 (15%) patients have returned to the fertility clinic with a desire for pregnancy. Of those, 12 (38.7%) patients had preserved ovarian function and underwent ART treatment with fresh oocytes, resulting in nine (75%) livebirth. The remaining 19 (61.3%) patients requested warming of their cryopreserved material because of ovarian insufficiency. Of those, eight (42.1%) patients had a livebirth, of whom three after OTO-IVM. To date, 5/207 patients (2.4%) achieved an ongoing pregnancy or livebirth after spontaneous conception.

LIMITATIONS, REASONS FOR CAUTION

Our FP programme is based on a patient-tailored approach rather than based on an efficiency-driven algorithm. The data presented are descriptive, which precludes firm conclusions.

WIDER IMPLICATIONS OF THE FINDINGS

Combining different FP procedures is likely to enhance the reproductive fitness of patients undergoing gonadotoxic treatment but further follow-up studies are needed to confirm this.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was used for this study and the authors have no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

[Neuromuscular disease: health care accessibility in the Nord-Pas-de- Calais region]

A survey was conducted to estimate accessibility to current diagnostic techniques for patients with neuromuscular disease living in the Nord-Pas-de-Calais. In association with the "Association française contre les myopathies", we invited 200 adults with neuromuscular disease to fill out a questionnaire concerning diagnosis of their neuromuscular disease and medical and paramedical follow-up. Each subject answered the questionnaire anonymously providing data on sociodemographic items, diagnosis and medical and paramedical follow-up. The results showed a lack of follow-up for lung disease whereas respiratory failure is known as a frequent complication of neuromuscular disease. Genetic counselling was not suggested often enough. A large proportion (80 p. 100) of the patients had had physiotherapy. Whereas cardiomyopathy and orthopedic buckling with subsequent decreased autonomy are observed in 90 p. 100 of patients with Duchenne muscular dystrophy, only 42 p. 100 of the patients with this disease were followed by a cardiologist and a physical therapists. We suggest more cooperation between specialists in order to improve medical care for patients with neuromuscular diseases.

Six DNA polymorphisms in the low density lipoprotein receptor gene: their genetic relationship and an example of their use for identifying affected relatives of patients with familial hypercholesterolaemia

We have determined the relative allele frequency and estimated linkage disequilibrium between six DNA polymorphisms of the low density lipoprotein (LDL) receptor gene. Polymorphisms were detected using the enzymes SfaNI, TaqI, StuI, HincII, AvaII, and NcoI after DNA amplification by the polymerase chain reaction. Strong linkage disequilibrium was detected between many of the pair wise comparisons in a sample of 60 patients heterozygous for familial hypercholesterolaemia (FH). Using the enzymes HincII, NcoI, and SfaNI, 85% of patients were heterozygous for at least one polymorphism and thus potentially informative for cosegregation studies. The polymorphisms were used to follow the inheritance of the defective allele of the LDL receptor gene in the relatives of a patient with FH. Assays of LDL receptor activity on lymphoblastoid cell lines from two members of the family was used to confirm that the proband, but not the hypercholesterolaemic brother, had a defect in the LDL receptor. In the family, none of the children had inherited the allele of the LDL receptor gene inferred to be defective. The problems associated with this cosegregation approach to identify relatives of patients with a clinical diagnosis of FH are discussed.

Interaction of LpB, LpB:E, LpB:C-III, and LpB:C-III:E lipoproteins with the low density lipoprotein receptor of HeLa cells

In this study we measured the binding parameters of different apolipoprotein (apo) B-containing lipoproteins to the low density lipoprotein (LDL) receptor of HeLa cells. Our goal was to determine the respective roles of the different apolipoproteins of these particles, with particular emphasis on apos B, E, and C-III. Very low density lipoprotein from hypertriglyceridemic subjects (B to E molar ratio = 1:16) bound to HeLa cells with an affinity higher than that of LDL, but the apparent number of binding sites per cell was lower. Because of the heterogeneity of these lipoproteins, which were isolated by ultracentrifugation, we used immunoaffinity chromatography to define these particles on the basis of their apolipoprotein content. Lipoprotein B (LpB) particles that contained apo B as their sole apolipoprotein had lower affinity for the LDL receptor than did total LDL but had an apparently higher number of binding sites. The presence of apo E of phenotype E3/E3 or E4/E4 on one particle increased the affinity of the apo B-containing lipoprotein for the LDL receptor. The apparent number of binding sites decreased, probably due to the fact that a lipoprotein particle containing multiple copies of apo E bound to more than one molecule of LDL receptor. Interaction with several LDL receptors would also explain the higher binding affinity that we observed. The calculated number of binding sites expressed for each apo E molecule is close to the number of binding sites for lipoproteins containing only apo B (LpB or LDL), indicating that each apo E can interact with one LDL receptor. When the apo E phenotype was E2/E2, the LpB:E lipoproteins did not bind to the LDL receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Recherches sur les composés éthyléniques. V. Liens entre la structure des akènes et leur fréquence de vibration νC = C influence des effets structuraux et établissement d'une relation de topo-information

An examination of spectroscopic data for 43 alkenes reveals the influence of increasing substitution at the carbon atoms α or β to the ethylenic bond. The presence of a particularly large steric constraint requires that there be a single preferred molecular conformation: in such a case the frequency of the νC = C vibrator is strongly decreased (10 cm−1).A quantitative analysis of the phenomenon can be achieved using the "topological-chemical method D.A.R.C.". Topologic-information relationships could be developed for the two series 2-alkylethylenes and 2,2-dialkylethylenes. These permit the calculation of the contribution of each topological site to the frequency νC = C. For the first series, the relationship, based on 9 compounds, permits predictions about 30 others. For the second series, deductions are made concerning 159 compounds from a relationship established on a base of 13 compounds. [Journal translation]