Reproductive biomedicine online最新文献

In this era of the freeze-all strategy, the prevalence of frozen embryo transfer (FET) cycles is increasing rapidly. Although still quite often used, the hormone replacement therapy cycle to prepare a FET should now belong to the past, unless strictly necessary. This raises questions about possible flexible protocols for the preparation of an FET cycle in a (modified) natural cycle. In this viewpoint, an overview of the different options is discussed, stressing the importance of the corpus luteum.

Research question

Should ovulation be triggered in a modified natural cycle (mNC) with recombinant human chorionic gonadotrophin (rHCG) as soon as a mean follicle diameter of 17 mm is visible, or is more flexible planning possible?

Design

This multicentre, retrospective, observational study of 3087 single frozen blastocyst transfers in mNC was carried out between January 2020 and September 2022. The inclusion criteria included endometrial thickness ≥7 mm and serum progesterone <1.5 ng/ml. The main outcome was ongoing pregnancy rate. Secondary end-points were pregnancy rate, implantation rate, clinical pregnancy rate and miscarriage rate. The mean follicle size at triggering was stratified into three groups (13.0–15.9, 16.0–18.9 and 19.0–22 mm).

Results

The baseline characteristics between the groups did not vary significantly for age, body mass index and the donor's age for egg donation. No differences were found in pregnancy rate (64.5%, 60.2% and 57.4%; P = 0.19), clinical pregnancy rate (60.5%, 52.8% and 50.6%; P = 0.10), implantation rate (62.10%, 52.9% and 51.0%; P = 0.05) or miscarriage rate (15.0%, 22.2%; and 25.0%; P = 0.11). Although ongoing pregnancy rate (54.9%, 46.8% and 43.1%; P = 0.02) varied significantly in the univariable analysis, it was no longer significant after adjustment for the use of preimplantation genetic testing for aneuploidies and egg donation.

Conclusions

The findings showed rHCG could be flexibly administered with a mean follicle size between 13 and 22 mm as long as adequate endometrial characteristics are met, and serum progesterone is <1.5 ng/ml. Considering the follicular growth rate of 1–1.5 mm/day, this approach could allow a flexibility for FET scheduling of 6–7 days, simplifying mNC FET planning in clinical practice.

Research question

How do perinatal outcomes differ between programmed and modified natural frozen embryo transfer (FET) cycles?

Design

A retrospective cohort study of 839 patients was undertaken at a university-affiliated fertility practice undergoing single blastocyst FET cycles between 2014 and 2020. The primary outcome measures were the incidence of ischaemic placental disease, small for gestational age (SGA), intrauterine growth restriction (IUGR), preterm delivery, birth weight, and mode of delivery.

Results

When comparing programmed FET cycles with modified natural FET cycles, there was no increased risk of ischaemic placental disease [adjusted risk ratio (aRR) 0.83, 95% CI 0.61–1.14], IUGR (unadjusted RR 0.50, 95% CI 0.14–1.77), preterm delivery (aRR 1.11, 95% CI 0.72–1.70) or SGA (aRR 0.69, 95% CI 0.40–1.19). Patients in the programmed cohort had increased risk of caesarean delivery (aRR 1.32, 95% CI 1.10–1.59). These outcomes were unchanged when limited to patients undergoing their first FET cycle.

Conclusions

There are no differences in patient and neonatal clinical outcomes between programmed and modified natural FET cycles. The choice of FET protocol should remain a shared decision between patient and provider.

Research question

What areas of manual IVF cryostorage operations are common to the safe operation of IVF cryostorage facilities and require effort from embryologists?

Design

Observational time and motion data were collected by two observers equipped with the digital cameras over 2 weeks at four well-characterized US IVF centres (sites α, β, γ and δ) from 12 participants performing cryostorage tasks. To understand the work processes of the different sites and assist in the data analysis, informal interviews were conducted with the study participants and laboratory directors. Data were analysed to identify work processes that might be eliminated or diminished by automation and software improvements.

Results

On average, it took 3.4 data record queries per retrieval from cryostorage to identify a cane, while the canister was lifted an average of 1.5 times per retrieval, with a mean 11.8 ± 9.2 s per lift. Of the total time spent working with cryostorage equipment, 47.25% was of a fatiguing nature. Sites α, β and γ utilized one person to fill the liquid nitrogen storage Dewars, while site δ had two technicians working in tandem to move and fill the Dewars, with different frequencies and determination factors for refills and efficiencies.

Conclusions

This time and motion study demonstrated significant time investment, task redundancy and fatiguing working conditions among embryologists using manual cryostorage processes. There was a disparity of processes and space capacity across different laboratories. Some of these issues may be addressed by the integration of automation and technology solutions.

Research question

Is artificial oocyte activation (AOA) effective for patients with unexplained low or no fertilization following IVF/intracytoplasmic sperm injection (ICSI)?

Design

All IVF/ICSI cases resulting in total fertilization failure or fertilization rate ≤25% at Ninewells Assisted Conception Unit, Dundee between January 2014 and December 2021 (n = 231) were reviewed contemporaneously. After exclusion of obvious stimulation, egg, sperm and/or assisted reproductive technology laboratory factors, patients with at least one cycle of IVF/ICSI resulting in apparently unexplained fertilization abnormalities were offered research investigations, including sperm immunocytochemistry for phospholipase C zeta (PLCζ) protein expression. This retrospective case–control cohort study evaluated laboratory and clinical outcomes for 39 couples (15 attended for sperm studies research) that subsequently undertook ICSI-AOA with Ca²⁺ ionophore.

Results

Comparing preceding IVF/ICSI and subsequent ICSI-AOA for each patient, the number of eggs collected was similar; however, ICSI-AOA resulted in a significantly improved fertilization rate (57.2% versus 7.1%; P < 0.0001). The uplift for a subset of 10 patients identified with PLCζ deficiency was 66.3% versus 4.6% (P < 0.0001). Overall, ICSI-AOA resulted in a higher number of fresh embryo transfers (94.6% versus 33.3%; P < 0.0001), a significantly higher clinical pregnancy rate (CPR) and live birth rate (LBR; 18.9% versus 2.6%; P = 0.02), a significant increase in cycles with surplus embryos suitable for cryostorage (43.6% versus 0%; P < 0.0001), and increased cumulative CPR (41.0% versus 2.6%; P < 0.0001) and LBR (38.5% versus 2.6%; P < 0.0001).

Conclusion

AOA is a powerful tool that can transform clinical outcomes for couples experiencing apparently unexplained fertilization abnormalities. PLCζ assays have the potential to be valuable diagnostic tools to determine patient selection for ICSI-AOA, and research efforts should continue to focus on their development.

Research question

What is the effect of embryo morphology score on 14-day β-HCG levels and 14–18-day β-HCG doubling values, and do they have differences in day-3 embryo or day-5 blastocyst transfers?

Design

Retrospective analysis of 4434 fresh cycles of single embryo transfers (SET) with β-HCG ≥15 mIU/ml on day 14 after transfer via IVF and ICSI. The correlation between embryo morphology score and 14-day β-HCG was examined. Doubling of 14–18 day β-HCG was analysed in 2628 cycles to determine correlations with embryo morphology score.

Results

In day-3 SET, number of embryonic cells was positively correlated with 14-day post-transfer β-HCG values (R = 0.076; P = 0.013). No significant correlation was observed between the grade of the transferred embryos and the 14–18-day serum β-HCG doubling values. In day-5 single blastocyst transfers, the degree of blastocyst expansion, trophoblast cell and inner cell mass (ICM) grades demonstrated a significant positive correlation with 14-day post-transfer β-HCG (P < 0.001, P = 0.014, P = 0.003). Degree of blastocyst expansion was significantly correlated with 14–18-day β-HCG doubling values (R = –0.051, P = 0.027). Grades of the ICM and trophoblast cells showed no significant correlation with 14–18-day β-HCG doubling values.

Conclusion

In fresh SET, embryo morphology score influences 14-day β-HCG values in day-3 embryos and day-5 blastocyst transfers. Embryo morphology score in day-3 SET does not affect 14–18-day β-HCG doubling values. Degree of blastocyst expansion significantly affects 14–18-day β-HCG doubling values in day-5 blastocyst transfers.

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A century ago, Sampson identified three uterine anatomical structures that may determine the amount of retrograde menstruation and the likelihood of the development of endometriosis: the cervix, the intramural portion of the fallopian tubes, and the myometrium. Critical appraisal was undertaken of data published over the last 40 years on the potential effect of the characteristics of these three anatomical variables on the risk of endometriosis. There is some evidence to support the pathogenic role of the diameter of the cervical canal, stenosis of internal or external orifices, and stiffness of cervical tissue. One study showed a significant association between the morphology of the intramural tubal tract and the frequency of endometriosis. A large body of evidence points to abnormalities of the myometrial structure as the anatomical aberration most consistently associated with endometriosis. These abnormalities have largely been interpreted as signs of early-onset adenomyosis, which may precede endometriosis and even lead to its development by increasing the amount of retrograde menstruation. Future research should aim to verify whether a positive relationship exists between the substantially increased number of ovulatory menses occurring in the decade following menarche, the development of anatomical myometrial abnormalities, changes in the amount of retrograde menstruation over time, and the risk of endometriosis.