Should we consider day-2 and day-3 embryo morphology before day-5 transfer when blastocysts reach a similar good quality?

Clinical outcomes of 291 day-5 blastocyst transfers carried out between January 2012 and March 2016 were retrospectively compared according to their quality at day 2 and 3. Inclusion criteria were female age younger than 37 years; first or second IVF and intracytoplasmic sperm injection cycle; quality of the transferred blastocyst: blastocoele B3 or higher; inner-cell-mass A/B; trophectoderm A/B; and known implantation outcome for each transferred blastocyst. Blastocysts were classified into good-quality and poor-quality embryo groups at day 2 and 3. Implantation (38.7% versus 41.4), clinical pregnancy (40.3% versus 45.9%), miscarriage (22.2% versus 26.7%;) and live birth rates (37.4% versus 38.8%) were comparable in day 2 good and poor-quality embryo groups. No signficiant differences in morphology of transferred blastocysts at day 3 were found. Multivariable analysis highlighted that poor or good embryo quality at day 2 and day 3 were not predictive of the implantation of good-quality blastocysts (at day 2: adjusted odds ratio = 0.82 CI 95% 0.49 to 1.38; at day 3: adjusted odds ratio = 1.39; CI 95% 0.77 to 2.52). Good-quality blastocyst transfer should, therefore, be carried out irrespective of embryo quality at cleavage stage, as it may not compromise success rates in a good-prognosis population.

Impact of oxygen tension during in vitro maturation: a sibling-oocyte prospective double-blinded study.

OBJECTIVE: To determine whether oxygen (O2) tension (20% vs. 5%) has an impact on oocyte maturation rates and morphology during in vitro maturation (IVM). DESIGN: A prospective, observational, monocentric, sibling-oocyte study. SETTING: University Hospital. PATIENTS: A total of 143 patients who underwent IVM for fertility preservation purposes from November 2016 to April 2021 were analyzed. Patients were included when ≥2 cumulus-oocyte complexes (COCs) were retrieved. The cohort of COCs obtained for each patient was randomly split into two groups: group 20% O2 and group 5% O2. INTERVENTION: Cumulus-oocyte complexes were incubated for 48 hours either under 5% O2 or 20% O2. After 24 and 48 hours of culture, every oocyte was assessed for maturity and morphology, to estimate oocyte quality. Morphology was evaluated considering six parameters (shape, size, ooplasm, perivitelline space, zona pellucida, and polar body characteristics), giving a total oocyte score ranging from -6 to +6. MAIN OUTCOME MEASURES: Maturation rates and total oocyte scores were compared using paired-sample analysis between group 20% O2 and group 5% O2. RESULTS: Patient median age was 31.4 [28.1-35.2] years-old. The mean serum antimüllerian hormone levels and antral follicle count were 3.2 ± 2.3 ng/mL and 27.2 ± 16.0 follicles, respectively. A mean of 10.7 COCs per cycle were retrieved, leading to 6.1 ± 2.4 metaphase II oocytes vitrified (total maturation rate = 57.3%; 991 metaphase II oocytes/1,728 COCs). A total of 864 COCs were included in each group. Oocyte maturation rates were not different between the two groups (group 20% O2: 56.82% vs. group 5% O2: 57.87%, respectively). Regarding oocyte morphology, the mean total oocyte score was significantly higher in group 5% O2 compared with group 20% O2 (3.44 ± 1.26 vs. 3.16 ± 1.32, P=.014). CONCLUSION: As culture under low O2 tension (5% O2) improves oocyte morphology IVM, our results suggest that culture under hypoxia should be standardized. Additional studies are warranted to assess the impact of O2 tension on oocyte maturation and the benefit of IVM under low O2 tension for embryo culture after utilization of frozen material.

Fertility outcomes several years after urgent fertility preservation for patients with breast cancer.

OBJECTIVE: To study the fertility outcomes of women who tried to conceive after breast cancer (BC) treatment and fertility preservation. DESIGN: Retrospective observational, bicentric cohort study. SETTING: University hospital. PATIENTS: Patients with BC. INTERVENTION: All patients who had undergone fertility preservation before BC treatment between January 2013 and July 2019 were included (n = 844). The endpoint date was March 1, 2022. Patients with missing data on pregnancy attempts after a cancer diagnosis (n = 195) were excluded from the pregnancy analysis. MAIN OUTCOME MEASURES: Cumulative incidences of pregnancy and live birth (LB) were calculated. For women who became pregnant, the time to conception was calculated between the first fertility preservation consultation and the estimated day of conception. For those who did not conceive, we considered the time between the first fertility preservation consultation and the endpoint date, or the date of patient death. A Cox regression model was used to study the predictive factors for pregnancy and LB. RESULTS: Among the 649 patients with available data on pregnancy attempts after BC diagnosis, 255 (39.3% [35.5-43.2]) tried to conceive (median follow-up of 6.5 years). Overall, 135 (52.9% [46.6-59.2]) of these patients achieved a pregnancy, mainly through unassisted conception (79.3% [72.8-84.8]), and 99 reported an LB (representing 38.8% of patients who attempted conception). In our cohort, 48 months after the first fertility preservation consultation, the cumulative incidence of pregnancy was 33.1% ([27.6-37.9]). After adjustment for age, parity, type of chemotherapy administration, and endocrine therapy, only multiparity at diagnosis and absence of chemotherapy were positive predictive factors of pregnancy after cancer. Of the 793 patients who had vitrified oocytes and embryos, 68 used them (27% [21.3-32.5] of the patients who tried to conceive), resulting in 8 LBs (11.8% [5.2-21.9]). Women who used their cryopreserved oocytes and embryos were older at the first consultation of fertility preservation (hazard ratio 1.71 [1.42-2.21]), and chose more often to vitrify embryos (hazard ratio 1.76 [1.28-2.23]). CONCLUSION: Although pregnancy rates after fertility preservation for patients with BC are low, most conceptions are achieved without medical assistance. Our findings provide useful information to advise women on the different techniques of fertility preservation, their efficacy, and safety, as well as the relatively high chances of unassisted conception.