Assisted reproductive technology in Japan: A summary report for 2019 by the Ethics Committee of the Japan Society of Obstetrics and Gynecology

Effect of estrogen exposure on pregnancy outcomes in artificial frozen-thawed embryo transfer cycles

In contemporary times, the employment of vitrification freezing technology has led to the widespread adoption of frozen-thawed embryo transfer (FET) worldwide. Meanwhile, hormone replacement therapy (HRT) is a crucial protocol for priming the endometrium during FET cycles. Estrogen is required in HRT cycles for the induction of progesterone receptors and to promote endometrial thickness. However, there is no universal consensus on the treatment duration, dosage regimen, administration route, and target serum estrogen levels. Therefore, this study aimed to offer a comprehensive review of these topics. A shorter duration of estrogen exposure may elevate the risk of early miscarriage, while prolonged exposure to estrogen does not seem to confer advantages to general population and may be attempted in individuals with thin endometrium. Moreover, excessive estrogen levels on the day of progesterone administration may be associated with higher miscarriage rates and lower live birth rates (LBR). To offer more comprehensive guidance for clinical practice, extensive and prospective studies involving a large sample size are warranted to determine the optimal concentration and duration of estrogen exposure.

Formation of the first plane of division relative to the pronuclear axis predicts embryonic ploidy

RESEARCH QUESTION

Is there a relationship between the pronuclear axis and the first cleavage plane formation in human pronuclear-stage embryos, and what are the effects on ploidy and clinical pregnancy rates?

DESIGN

Transferred embryos were followed up until their prognoses. A total of 762 embryos formed two cells and reached the blastocyst stage after normal fertilization in a time-lapse incubator. Embryos were classified into three groups: group A: embryos in which the first plane of division was formed parallel to the axis of the pronucleus; group B: embryos in which cases of oblique formation were observed; and group C: embryos in which cases of perpendicular formation were observed.

RESULTS

The euploidy rate was significantly higher in groups A and B than those in group C (P < 0.01), whereas the aneuploidy rate was significantly higher in group C (P < 0.01) than in groups A and B. No differences were found between the three groups in frequency of positive HCG-based pregnancy tests, frequency of clinical pregnancies, miscarriage rates or delivery rates.

CONCLUSIONS

The formation pattern of the first plane of division relative to the pronuclear axis was a predictor of embryonic ploidy, with a reduced rate of euploidy and a high probability of aneuploidy observed when the first plane of division was perpendicular to the pronuclear axis.

Endometrial senescence is mediated by interleukin 17 receptor B signaling

BACKGROUND

We previously identified Il17RB, a member of the IL17 superfamily, as a candidate marker gene for endometrial aging. While IL17RB has been linked to inflammation and malignancies in several organ systems, its function in the endometrium has not been investigated and is thus poorly understood. In the present study, we performed a functional analysis of this receptor with the aim of determining the effects of its age-associated overexpression on the uterine environment.

METHODS

We analyzed IL17RB-related signaling pathways and downstream gene expression in an immortalized human endometrial glandular epithelial cell line ("hEM") forced to express the receptor via lentiviral transduction ("IL17RB-hEM"). We also prepared endometrial organoids from human endometrial tissue sourced from hysterectomy patients ("patient-derived EOs") and exposed them to cytokines that are upregulated by IL17RB expression to investigate changes in organoid-forming capacity and senescence markers. We analyzed RNA-seq data (GEO accession number GSE132886) from our previous study to identify the signaling pathways associated with altered IL17RB expression. We also analyzed the effects of the JNK pathway on organoid-forming capacity.

RESULTS

Stimulation with interleukin 17B enhanced the NF-κB pathway in IL17RB-hEM, resulting in significantly elevated expression of the genes encoding the senescence associated secretory phenotype (SASP) factors IL6, IL8, and IL1β. Of these cytokines, IL1β inhibited endometrial organoid growth. Bioinformatics analysis showed that the JNK signaling pathway was associated with age-related variation in IL17RB expression. When IL17RB-positive cells were cultured in the presence of IL17B, their organoid-forming capacity was slightly but non-significantly lower than in unexposed IL17RB-positive cells, but when IL17B was paired with a JNK inhibitor (SP600125), it was restored to control levels. Further, IL1β exposure significantly reduced organoid-forming capacity and increased p21 expression in endometrial organoids relative to non-exposure (control), but when IL1β was paired with SP600125, both indicators were restored to levels comparable to the control condition.

CONCLUSIONS

We have revealed an association between IL17RB, whose expression increases in the endometrial glandular epithelium with advancing age, and cellular senescence. Using human endometrial organoids as in vitro model, we found that IL1β inhibits cell proliferation and leads to endometrial senescence via the JNK pathway.

Oncologic, fertility, and obstetric outcomes with MPA therapy in women with endometrial cancer and atypical endometrial hyperplasia

AIM

Medroxyprogesterone acetate (MPA) is one of the treatments of atypical endometrial hyperplasia (AEH) and endometrial cancer (EC) to preserve the fertility. Efficacy of MPA therapy and fertility and obstetric outcomes after remission were evaluated in EC or AEH patients.

METHODS

Among patients diagnosed with EC or AEH at Tokushima University Hospital between January 2002 and October 2020, we retrospectively analyzed patients, ages range from 26 to 40, who underwent conservative management using MPA (400-600 mg/day).

RESULTS

In total, 19 patients underwent MPA therapy. The 18 (94%) patients achieved complete response (CR), and 1 (5%) patient achieved partial response (PR). Relapse occurred in 6 (32%) patients who had achieved CR. Of the patients who relapsed, 4 patients resumed MPA therapy and were in remission. Among 19 patients, 13 patients attempted pregnancy after CR. All of them underwent ovulation induction or assisted reproductive technology. As a result, 20 pregnancies in 10 (77%) patients and 12 live births in 9 (69%) patients were achieved. Rate of spontaneous abortion was 35% (7/20).

CONCLUSIONS

MPA therapy can produce a high remission rate, and be considered an effective treatment for patients who wish fertility preservation. Around 70% patients who attempt to pregnancy can have at least one baby by infertility treatments. Because recurrence rate after MPA therapy is high, it may be desirable to aim for early pregnancy by active intervention.

Assisted reproductive technology-associated risk factors for retained products of conception

OBJECTIVE

To evaluate assisted reproductive technology-associated risk factors for retained products of conception among live births.

DESIGN

Registry-based retrospective cohort study.

SETTING

Not applicable.

PATIENT(S)

Cycle-specific data for a total of 369,608 singleton live births after fresh and frozen-thawed embryo transfers (FETs) between 2007 and 2017 were obtained from the Japanese assisted reproductive technology registry.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Retained products of conception after delivery. Odds ratios and 95% confidence intervals for risk factors associated with retained products of conception during fresh and frozen cycles.

RESULT(S)

In total, 132 deliveries (0.04% of eligible assisted reproductive technology registry deliveries) had retained products of conception; 122 (92.4%) of these deliveries occurred after FET transfer cycles. Cases with retained products of conception were significantly more likely to have undergone vaginal delivery than cases without retained products of conception (78.0% vs. 61.1%); they were also more likely to have been complicated with the placenta accreta spectrum (24.2% vs. 0.45%). Among patients undergoing FETs, factors associated with a significantly increased risk of retained products of conception were embryo stage at transfer, use of hormone replacement cycles, and assisted hatching. Use of hormone replacement cycles represented the largest risk factor (adjusted odds ratio, 4.9; 95% confidence interval, 2.0-12.4), such that retained products of conception occurred in 0.05% (51 of 97,958) of deliveries after hormone replacement cycles but only 0.01% (5 of 47,079) of deliveries after natural cycles. Subgroup analysis showed that hormone replacement cycles and assisted hatching remained significant risk factors for retained products of conception in cases without polycystic ovary syndrome and anovulation and cases with vaginal delivery, but not cases with cesarean section. Among fresh embryo transfers, an increased number of retrieved oocytes was the only significant risk factor for retained products of conception.

CONCLUSION(S)

Our analyses demonstrated that most of the cases involving retained products of conception were derived from FETs, and we identified the use of hormone replacement cycles as the largest risk factor for retained products of conception within this group.

Alternatives to in vitro fertilization

There have been concerns on the potential overuse of in vitro fertilization (IVF) in view of the lack of evidence on effectiveness in certain populations, potential short and long-term safety risks, and economic considerations. On the other hand, the use of alternatives to IVF seems to be underappreciated in clinical practice as well as research. In this review, we summarized the up-to-date evidence on the effectiveness, safety as well as cost-effectiveness of different alternatives to IVF, including expectant management, intrauterine insemination, tubal flushing, in vitro maturation as well as intravaginal culture. We also discussed the trend of IVF use over the last decade and the available tiers of service because of intravaginal culture, and revisited the roles of different alternatives to IVF in modern reproductive medicine from both clinical and research perspectives.

Post-warming culture of human vitrified blastocysts with prolactin improves trophoblast outgrowth

BACKGROUND

Human embryos express the prolactin (PRL) receptor at the morula and blastocyst stages. Treatment with PRL from cleavage to the blastocyst stage improves blastocyst outgrowth on fibronectin-coated dishes. However, whether post-warming PRL treatment of blastocysts cultured without PRL could improve outgrowth competence remains unknown. Furthermore, the optimal time for post-warming PRL treatment remains to be ascertained. This study investigated the effects of PRL treatment during recovery culture on human blastocyst outgrowth and its related genes.

METHODS

In total, 374 discarded vitrified blastocysts were randomly allocated to two groups, to be cultured with (n = 208) or without PRL (control; n = 166) for 120 min for recovery, and then plated on fibronectin-coated dishes. The expression level of PRL-interacting genes, blastocyst adhesion rate, outgrowth area, distance of trophoblast migration, and outgrowth degeneration were examined.

RESULTS

The mRNA expression of ezrin, radixin, and moesin, which regulate cell adhesion and invasion by controlling actin reorganization during epithelial-to-mesenchymal transition (EMT), was stimulated by PRL treatment for 120 min. The expression of EMT-related genes, transforming growth factor β1, snail1, and twist1 was also promoted following treatment with PRL for 120 min. PRL-treated blastocysts also exhibited augmented expression of cadherin 2 and transcriptional repression of cadherin 1. Higher mRNA expression of integrin-based focal adhesion-related genes, ITGA5 and ITGB1, was observed after treatment with PRL for 120 min than in the non- and shorter-treatment groups. PRL treatment for 120 min did not alter the rate of blastocyst adhesion to fibronectin-coated dishes 96 h after the outgrowth culture assay. However, multiple linear regression analysis revealed that the outgrowth area was significantly increased in PRL-treated blastocysts. The migration distance of trophoblast cells was significantly increased and degeneration rate was significantly decreased after PRL treatment. Furthermore, a more beneficial effect of PRL treatment on blastocyst outgrowth was observed when the blastocysts were vitrified on day 5 than when they were vitrified on day 6.

CONCLUSIONS

Post-warming culture of human vitrified blastocysts with PRL for 120 min promoted trophoblast outgrowth in vitrified human blastocysts. Furthermore, PRL treatment may reduce outgrowth degeneration by increasing resistance to apoptosis during trophoblast migration.

Fatty acid supplementation into warming solutions improves pregnancy outcomes after single vitrified-warmed cleavage stage embryo transfers

Purpose

This study aimed to examine the embryonic development of human 4-cell stage embryos after warming with fatty acids (FAs) and to assess the pregnancy outcomes after single vitrified-warmed cleavage stage embryo transfers (SVCTs).

Methods

Experimental study: A total of 217 discarded, vitrified human 4-cell stage embryos donated for research by consenting couples were used. The embryos were warmed using the fatty acid (FA)-supplemented solutions (FA group) or nonsupplemented solutions (control group). The developmental rate, morphokinetics, and outgrowth competence were analyzed. Clinical study: The treatment records of women undergoing SVCT in natural cycles between April and September 2022 were retrospectively analyzed (April-June 2022, control group; July-September 2022, FA group).

Results

Experimental study: The rate of morphologically good blastocysts was significantly higher in the FA group than in the control group (p = 0.0302). The morphokinetics during cleavage, morula, and blastocyst stages were comparable between the groups. The outgrowth was significantly increased in the FA group (p = 0.0438). Clinical study: The rates of implantation, clinical pregnancy, and ongoing pregnancy after SVCTs were significantly increased in the FA group (p = 0.0223-0.0281).

Conclusions

Fatty acid-supplemented warming solutions effectively improve embryo development to the blastocyst stage and pregnancy outcomes after SVCTs.

Effects of undernutrition and low energy availability on reproductive functions and their underlying neuroendocrine mechanisms

It has been well established that undernutrition and low energy availability disturb female reproductive functions in humans and many animal species. These reproductive dysfunctions are mainly caused by alterations of some hypothalamic factors, and consequent reduction of gonadotrophin-releasing hormone (GnRH) secretion. Evidence from literature suggests that increased activity of orexigenic factors and decreased activity of anorexigenic/satiety-related factors in undernourished conditions attenuate GnRH secretion in an integrated manner. Likewise, the activity of kisspeptin neurons, which is a potent stimulator of GnRH, is also reduced in undernourished conditions. In addition, it has been suggested that gonadotrophin-inhibitory hormone, which has anti-GnRH and gonadotrophic effects, may be involved in reproductive dysfunctions under several kinds of stress conditions. It should be remembered that these alterations, i.e., promotion of feeding behavior and temporary suppression of reproductive functions, are induced to prioritize the survival of individual over that of species, and that improvements in metabolic and nutritional conditions should be considered with the highest priority.

Rupture Prediction for Microscopic Oocyte Images of Piezo Intracytoplasmic Sperm Injection by Principal Component Analysis

Assisted reproductive technology (ART) has progressed rapidly, resulting in a great improvement in the clinical pregnancy ratio. When applying the protocol of piezo intracytoplasmic sperm injection (Piezo-ICSI), it is very important to puncture the zona pellucida and the oocyte cytoplasmic membrane without rupturing the oocyte cytoplasmic membrane. Previous studies have shown that the poor extensibility of the oocyte cytoplasmic membrane might be closely related to rupture. However, no consensus has been reached regarding how the quality of the oocyte for extensible ability or rupture possibility affects the surfaces of the oocyte on the microscopic frames. We conducted this study to provide evidence that artificial intelligence (AI) techniques are superior for predicting the tendency of oocyte rupture before puncturing on Piezo-ICSI. To inspect it, we provided a retrospective trial of 38 rupture oocytes and 55 nonruptured oocytes. This study marked the highest accuracy of 91.4% for predicting oocytes rupture using the support-vector machine method of machine learning. We conclude that AI technologies might serve an important role and provide a significant benefit to ART.

Out-of-pocket payment and patients' treatment choice for assisted reproductive technology by household income: a conjoint analysis using an online social research panel in Japan

BACKGROUND

Economic disparities affect access to assisted reproductive technology (ART) treatment in many countries. At the time of this survey, Japan provided partial reimbursement for ART treatment only for those in low- or middle-income classes due to limited governmental budgets. However, the optimal level of financial support by income class remains unclear.

METHODS

We conducted a conjoint analysis of ART in Japan in January 2020. We recruited 824 women with fertility problems aged 25 to 44 years via an online social research panel. They completed a questionnaire of 16 hypothetical scenarios measuring six relevant ART attributes (i.e., out-of-pocket payment, pregnancy rate, risk of adverse effects, number of visits to outpatient clinics, consultation hours and kindness of staff) and their relations to treatment choice.

RESULTS

Mixed-effect logistic regression models showed that all six attributes significantly influenced treatment preferences, with participants valuing out-of-pocket payment the most, followed by pregnancy rates and kindness of staff. Significant interactions occurred between high household income (≥ 8 million JPY) and high out-of-pocket payment (≥ 500,000 JPY). However, the average marginal probability of the highest-income patients (i.e., ≥ 10 million JPY, ineligible for the subsidy) receiving ART treatment at the average cost of 400,000 JPY was 47%, compared to 56 - 61% of other income participants, who opted to receive ART at an average cost of 100,000 JPY after a 300,000 JPY subsidy.

CONCLUSION

Our results suggest that out-of-pocket payment is the primary determinant in patients' decision to opt for ART treatment. High-income patients were more likely to choose treatment, even at a high cost, but their income-based ineligibility for government financial support might discourage some from receiving treatment.