Significant decrease of maternal mitochondria carryover using optimized spindle-chromosomal complex transfer.

Mutations in mitochondrial DNA (mtDNA) contribute to a variety of serious multi-organ human diseases, which are strictly inherited from the maternal germline. However, there is currently no curative treatment. Attention has been focused on preventing the transmission of mitochondrial diseases through mitochondrial replacement (MR) therapy, but levels of mutant mtDNA can often unexpectedly undergo significant changes known as mitochondrial genetic drift. Here, we proposed a novel strategy to perform spindle-chromosomal complex transfer (SCCT) with maximal residue removal (MRR) in metaphase II (MII) oocytes, thus hopefully eliminated the transmission of mtDNA diseases. With the MRR procedure, we initially investigated the proportions of mtDNA copy numbers in isolated karyoplasts to those of individual oocytes. Spindle-chromosomal morphology and copy number variation (CNV) analysis also confirmed the safety of this method. Then, we reconstructed oocytes by MRR-SCCT, which well developed to blastocysts with minimal mtDNA residue and normal chromosomal copy numbers. Meanwhile, we optimized the manipulation order between intracytoplasmic sperm injection (ICSI) and SCC transfer and concluded that ICSI-then-transfer was conducive to avoid premature activation of reconstructed oocytes in favor of normal fertilization. Offspring of mice generated by embryos transplantation in vivo and embryonic stem cells derivation further presented evidences for competitive development competence and stable mtDNA carryover without genetic drift. Importantly, we also successfully accomplished SCCT in human MII oocytes resulting in tiny mtDNA residue and excellent embryo development through MRR manipulation. Taken together, our preclinical mouse and human models of the MRR-SCCT strategy not only demonstrated efficient residue removal but also high compatibility with normal embryo development, thus could potentially be served as a feasible clinical treatment to prevent the transmission of inherited mtDNA diseases.

Bi-allelic variants in ASTL cause abnormal fertilization or oocyte maturation defects.

Fertilization is a fundamental process of development, and the blocking mechanisms act at the zona pellucida (ZP) and plasma membrane of the egg to prevent any additional sperm from binding, permeating and fusing after fertilization. In clinical practice, some couples undergoing recurrent IVF failures that mature oocytes had abnormal fertilization for unknown reason. Ovastacin encoded by ASTL cleave the ZP protein ZP2 and play a key role in preventing polyspermy. Here, we identified bi-allelic variants in ASTL that are mainly characterized by fertilization problems in humans. All four independent affected individuals had bi-allelic frameshift variants or predicted damaging missense variants, which follow a Mendelian recessive inheritance pattern. The frameshift variants significantly decreased the quantity of ASTL protein in vitro. And all missense variants affected the enzymatic activity that cleaves ZP2 in mouse egg in vitro. Three knock-in female mice (corresponding to three missense variants in patients) all show subfertility due to low embryo developmental potential. This work presents strong evidence that pathogenic variants in ASTL cause female infertility and provides a new genetic marker for the diagnosis of fertilization problems.

Bi-allelic missense variants in MEI4 cause preimplantation embryonic arrest and female infertility.

Preimplantation embryonic arrest is an important pathogenesis of female infertility, but little is known about the genetic factors behind this phenotype. MEI4 is an essential protein for DNA double-strand break formation during meiosis, and Mei4 knock-out female mice are viable but sterile, indicating that MEI4 plays a crucial role in reproduction. To date, MEI4 has not been found to be associated with any human reproductive diseases. Here, we identified six compound heterozygous and homozygous MEI4 variants-namely, c.293C > T, p.(Ser98Leu), c.401C > G, p.(Pro134Arg), c.391C > G, p.(Pro131Ala), c.914A > T, p.(Tyr305Phe), c.908C > G, p.(Ala303Gly), and c.899A > T, p.(Gln300Leu)-in four independent families that were responsible for female infertility mainly characterized by preimplantation embryonic arrest. In vitro, we found that these variants reduced the interaction between MEI4 and DNA. In vivo, we generated a knock-in mouse model and demonstrated that female mice were infertile and were characterized by developmental defects during oogenesis. Our findings reveal the important roles of MEI4 in human reproduction and provide a new diagnostic marker for genetic counseling of clinical infertility patients.

Effect of small follicles on clinical pregnancy and multiple pregnancy rates in intrauterine insemination: a cohort study.

STUDY QUESTION: What is the effect of small follicles on clinical pregnancy and multiple pregnancy rates in women undergoing IUI with ovarian stimulation (IUI-OS)? SUMMARY ANSWER: The presence of ≥2 small follicles with a diameter of 10-12 or 12-14 mm was associated with an increased chance of clinical pregnancy and the presence of any 12-14 mm or larger follicles, but not smaller follicles, was statistically significantly associated with an increased risk for multiple pregnancy. WHAT IS KNOWN ALREADY: IUI-OS is widely used as the first-line treatment for unexplained or mild male factor infertility. However, IUI is associated with the risk of multiple pregnancy. While the positive association between the number of follicles ≥14 mm and the chance of pregnancy and the risk of multiple pregnancy is known, the impact of smaller follicles is uncertain. STUDY DESIGN, SIZE, DURATION: This was a retrospective cohort study that included women undergoing IUI cycles from January 2007 to May 2021 in one assisted reproduction center. PARTICIPANTS/MATERIALS, SETTING, METHODS: We studied the impact of the number and size of follicles on trigger day on clinical pregnancy and multiple pregnancy rates. Generalized estimation equation regression models were used to compute unadjusted and adjusted odds ratios and 95% CI in all women and only women who achieved clinical pregnancy separately. The chance of clinical pregnancy and multiple pregnancy for different numbers of small follicles in cycles with one >18-mm follicle was calculated using marginal effects estimate. MAIN RESULTS AND THE ROLE OF CHANCE: This cohort included 12 933 IUI cycles in 7504 women. The overall clinical pregnancy rate was 16.1% (2081/12 933), with a multiple pregnancy rate of 10.5% (218/2081). In the adjusted analysis, the chance of clinical pregnancy increased significantly with the increase in the number of follicles with the diameter of 14-16, 16-18, and 18-20 mm. As for 10-12 mm [adjusted odds ratio (aOR) 1.22, 95% CI 1.02-1.46] and 12-14 mm (aOR 1.29, 95% CI 1.07-1.56) follicles, only groups with ≥2 follicles of those sizes showed significantly increased chance of clinical pregnancy. In cycles that led to pregnancy, follicles with the diameter of 12-14 mm were associated with an increased risk of multiple pregnancy (aOR 1.73, 95% CI 1.19-2.53 for one such follicle; aOR 2.27, 95% CI 1.44-3.56 for ≥2 such follicles), while 10- to 12-mm follicles were not significantly associated with multiple pregnancy (aOR 1.18, 95% CI 0.72-1.95 for ≥2 such follicles). The associations of multiple pregnancy were similar when including all cycles. LIMITATIONS, REASONS FOR CAUTION: This was a retrospective observational study from a single center. The records of follicle diameter in our center were of a 2-mm interval which limited our ability to analyze the size of follicle as a continuous variable. Also, the number of cycles with a high number of small follicles was still limited which impeded more detailed analysis on the ≥2 follicles subgroup. Similarly, the value of some parts of the marginal probability estimation for multiple pregnancy versus pregnancy according to size and number of follicles was also limited by the low sample size of certain combinations. WIDER IMPLICATIONS OF THE FINDINGS: Follicles larger than 10 mm, especially those ≥12 mm, may need to be clearly recorded during transvaginal ultrasound surveillance and their potential effects on both pregnancy and multiple pregnancy can be discussed with couples undergoing IUI. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the National Natural Science Foundation of China (Grant numbers 82201912, 82371651, and 82071615) and Shanghai Sailing Program (21YF1423200). B.W.M. is supported by an NHMRC Investigator grant (GNT1176437). B.W.M. reports consultancy for ObsEva and Merck and travel support from Merck. B.W.M. has received research funding from Ferring and Merck. The authors declare no other competing interests. TRIAL REGISTRATION NUMBER: N/A.

The press-assisted fusion scheme significantly mitigates the quantity of HVJ-E required in mitochondrial replacement techniques.

In brief: The impact of HVJ-E employed in mitochondrial replacement techniques (MRTs) on embryonic development remains uncertain. This study has exhibited the influence of HVJ-E utilized in MRTs on embryonic development and has devised a novel HVJ-E-induced fusion approach to curtail the amount of HVJ-E employed in MRTs. Abstract: Mitochondrial replacement techniques (MRTs) provide a viable option for women carrying pathogenic mitochondrial DNA (mtDNA) variants to conceive disease-free offspring with a genetic connection. In comparison to electrofusion, HVJ-E-induced fusion has been identified as the most promising approach for clinical translation of MRTs due to its absence of electrical interference. However, despite confirmation of the absence of RNA activity in HVJ-E, a reduction in blastocyst quality has been observed in various MRTs studies utilizing the HVJ-E-induced fusion scheme. Recent investigations have revealed a dose-dependent elevation of reactive oxygen species (ROS) levels in various cancer cells incubated with HVJ-E. However, the impact of HVJ-E as a sole determinant on embryonic development in MRTs remains unverified. This investigation establishes that the augmented concentration of HVJ-E utilized in the conventional HVJ-E fusion protocol is an autonomous variable that influences embryonic development in MRTs. This effect may be attributed to amplified DNA damage resulting from heightened levels of ROS in reconstructed embryos. To mitigate the presence of HVJ-E in reconstructed zygotes while maintaining optimal fusion efficiency in MRTs, a novel HVJ-E-induced fusion approach was devised, namely, press-assisted fusion. This technique offers potential advantages in reducing detrimental factors that impede embryo development in MRTs.

Identification novel mutations and phenotypic spectrum expanding in PATL2 in infertile women with IVF/ICSI failure.

AIM: Abnormalities in oocyte maturation, fertilization, and early embryonic development are major causes of primary infertility in women who are undergoing IVF/ICSI attempts. Although many genetic factors responsible for these abnormal phenotypes have been identified, there are more additional pathogenic genes and variants yet to be discovered. Previous studies confirmed that bi-allelic PATL2 deficiency is an important factor for female infertility. In this study, 935 infertile patients with IVF/ICSI failure were selected for whole-exome sequencing, and 18 probands carrying PATL2 variants with a recessive inheritance pattern were identified. METHODS: We estimated that the prevalence contributed by PATL2 was 1.93% (18/935) in our study cohort. RESULTS: 15 novel variants were found in those families, including c.1093C > T, c.1609dupA, c.1204C > T, c.643dupG, c.877-2A > G, c.1228C > G, c.925G > A, c.958G > A, c.4A > G, c.1258T > C, c.1337G > A, c.1264dupA, c.88G > T, c.1065-2A > G, and c.1271T > C. The amino acids altered by the corresponding variants were highly conserved in mammals, and in silico analysis and 3D molecular modeling suggested that the PATL2 mutants impaired the physiologic function of the resulting proteins. Diverse clinical phenotypes, including oocyte maturation defect, fertilization failure, and early embryonic arrest might result from different variants of PATL2. CONCLUSIONS: These results expand the spectrum of PATL2 variants and provide an important reference for genetic counseling for female infertility, and they increase our understanding of the mechanisms of oocyte maturation arrest caused by PATL2 deficiency.

ADGB variants cause asthenozoospermia and male infertility.

Asthenozoospermia is one of the main factors leading to male infertility, but the genetic mechanisms have not been fully elucidated. Variants in the androglobin (ADGB) gene were identified in an infertile male characterized by asthenozoospermia. The variants disrupted the binding of ADGB to calmodulin. Adgb-/- male mice were infertile due to reduced sperm concentration (< 1 × 106 /mL) and motility. Spermatogenesis was also abnormal, with malformation of both elongating and elongated spermatids, and there was an approximately twofold increase in apoptotic cells in the cauda epididymis. These exacerbated the decline in sperm motility. It is surprising that ICSI with testicular spermatids allows fertilization and eventually develops into blastocyst. Through mass spectrometry, we identified 42 candidate proteins that are involved in sperm assembly, flagella formation, and sperm motility interacting with ADGB. In particular, CFAP69 and SPEF2 were confirmed to bind to ADGB. Collectively, our study suggests the potential important role of ADGB in human fertility, revealing its relevance to spermatogenesis and infertility. This expands our knowledge of the genetic causes of asthenozoospermia and provides a theoretical basis for using ADGB as an underlying genetic marker for infertile males.

Bi-allelic Missense Pathogenic Variants in TRIP13 Cause Female Infertility Characterized by Oocyte Maturation Arrest.

Normal oocyte meiosis is a prerequisite for successful human reproduction, and abnormalities in the process will result in infertility. In 2016, we identified mutations in TUBB8 as responsible for human oocyte meiotic arrest. However, the underlying genetic factors for most affected individuals remain unknown. TRIP13, encoding an AAA-ATPase, is a key component of the spindle assembly checkpoint, and recurrent homozygous nonsense variants and a splicing variant in TRIP13 are reported to cause Wilms tumors in children. In this study, we identified homozygous and compound heterozygous missense pathogenic variants in TRIP13 responsible for female infertility mainly characterized by oocyte meiotic arrest in five individuals from four independent families. Individuals from three families suffered from oocyte maturation arrest, whereas the individual from the fourth family had abnormal zygote cleavage. All displayed only the infertility phenotype without Wilms tumors or any other abnormalities. In vitro and in vivo studies showed that the identified variants reduced the protein abundance of TRIP13 and caused its downstream molecule, HORMAD2, to accumulate in HeLa cells and in proband-derived lymphoblastoid cells. The chromosome mis-segregation assay showed that variants did not have any effects on mitosis. Injecting TRIP13 cRNA into oocytes from one affected individual was able to rescue the phenotype, which has implications for future therapeutic treatments. This study reports pathogenic variants in TRIP13 responsible for oocyte meiotic arrest, and it highlights the pivotal but different roles of TRIP13 in meiosis and mitosis. These findings also indicate that different dosage effects of mutant TRIP13 might result in two distinct human diseases.

Optimal lead follicle size in letrozole human menopausal gonadotrophin intrauterine insemination cycles with and without spontaneous LH surge.

RESEARCH QUESTION: What is the optimal lead follicle size in letrozole, human menopausal gonadotrophin and intrauterine insemination (IUI) cycles with and without spontaneous LH surges? DESIGN: This retrospective cohort study included 3797 letrozole HMG IUI cycles between January 2010 and May 2021. All cycles were divided into two groups: the HCG trigger group (trigger day LH ≤15 mIU/ml) and the spontaneous LH surge group (trigger day LH >15 mIU/ml). These two groups were subdivided into smaller groups based on the diameter of the follicles. The primary outcome measure was clinical pregnancy rate. Logistic regression analysis was conducted to explore other risk factors. RESULTS: In the HCG trigger group, the clinical pregnancy rate varied significantly, with rates of 20.8%, 14.9% and 11.8% for the 16.1-18.0, 18.1-20.0 and 20.1-22.0 mm groups, respectively (P = 0.005). In the spontaneous LH surge group, the pregnancy rate of follicles within 14.1-16.0 mm was significantly higher than that of follicles within 20.1-22.0 mm (adjusted OR 0.533, 95% CI 0.308 to 0.923, P = 0.025). Also, patients with two lead follicles were 2.569 times more likely to achieve a clinical pregnancy than those with only one lead follicle (adjusted OR 2.569, 95% CI 1.258 to 5.246, P = 0.010). The duration of infertility was also found to be a common influencing factor in both groups. CONCLUSIONS: The optimal lead follicle size was between 16.1 and 18.0 mm in HCG-triggered letrozole HMG IUI cycles. If the lead follicle size is relatively small (14.1-18.0 mm) when a spontaneous LH surge occurs, there is no need to cancel the IUI cycle.

Impact of recurrent pregnancy loss history on reproductive outcomes in women undergoing fertility treatment.

BACKGROUND: Recurrent pregnancy loss negatively affects the reproductive outcomes of natural conception. Preimplantation genetic testing for aneuploidies has been the focus of interventions in women with recurrent pregnancy loss. However, the risk of no embryos being available, high costs, and uncertainties surrounding its effectiveness limit its use. Factors beyond euploidy, such as an appropriate intrauterine environment, are also important for improving the reproductive outcomes in women with recurrent pregnancy loss. It remains unknown whether a history of recurrent pregnancy loss can affect reproductive outcomes after fertility treatment. OBJECTIVE: This study aimed to investigate the impact of history of recurrent pregnancy loss on the reproductive outcomes of women undergoing fertility treatment. STUDY DESIGN: This was a retrospective cohort study of women who underwent their first frozen embryo transfer cycle or intrauterine insemination cycle between January 2014 and July 2020 in Shanghai, China. We excluded couples with known karyotypic abnormalities (eg, balanced translocation) or uterine malformation. We performed multivariate binary logistic regressions for biochemical pregnancy, miscarriage, and live birth rates to investigate the associations between recurrent pregnancy loss history and reproductive outcomes. RESULTS: A total of 29,825 women who underwent frozen embryo transfer cycles and 5476 women who underwent intrauterine insemination cycles were included in this study. In those who underwent frozen embryo transfer, history of recurrent pregnancy loss was not significantly associated with biochemical pregnancy (adjusted odds ratio, 1.19; 95% confidence interval, 0.87-1.63), miscarriage (adjusted odds ratio, 0.99; 95% confidence interval, 0.78-1.26), or live birth rates (adjusted odds ratio, 0.91; 95% confidence interval, 0.79-1.06). Similarly, in frozen embryo transfer cycles that led to clinical pregnancy, recurrent pregnancy loss history was not significantly associated with live birth (adjusted odds ratio, 0.99; 95% confidence interval, 0.76-1.28) or miscarriage rates (adjusted odds ratio, 1.04; 95% confidence interval, 0.81-1.35). In women with intrauterine insemination, history of recurrent pregnancy loss showed no significant associations with fertility outcomes in all cycles ([adjusted odds ratio, 1.36; 95% confidence interval, 0.88-2.10] for live birth rate and [adjusted odds ratio, 1.74; 95% confidence interval, 0.75-4.01], for miscarriage rate) and in cycles that led to clinical pregnancy ([adjusted odds ratio, 0.70; 95% confidence interval, 0.31-1.63] for live birth rate and [adjusted odds ratio, 1.45; 95% confidence interval, 0.58-3.63] for miscarriage rate). CONCLUSION: In women without obvious chromosome abnormality and uterine malformation who undergo fertility treatment, recurrent pregnancy loss history was not significantly associated with miscarriage and live birth rates, suggesting that it has little or no prognostic value in predicting the reproductive outcomes of frozen embryo transfer or intrauterine insemination cycles.

Does Day 3 embryo status matter to reproductive outcomes of single blastocyst transfer cycles? A cohort study.

OBJECTIVE: To investigate whether Day 3 (D3) embryo status matter to reproductive outcomes of blastocyst transfer cycles. DESIGN: Retrospective cohort study. SETTING: Assisted Reproduction Department of Shanghai Ninth People's Hospital, Shanghai, China. POPULATION: A total of 6906 vitrified-thawed single blastocyst transfer cycles in 6502 women were included. METHODS: Generalised estimated equation regression models were used to calculate adjusted odds ratios (aOR) and 95% confidence intervals (CI) for the associations between embryo status and pregnancy outcomes. MAIN OUTCOME MEASURES: Biochemical pregnancy, miscarriage, live birth. RESULTS: High-quality blastocysts derived from poor-grade D3 embryos had comparable pregnancy outcomes to those derived from high-grade D3 embryos (40.0% versus 43.2%, aOR 1.00, 95% CI 0.85-1.17 for live birth rate; 8.3% versus 9.5%, aOR 0.82, 95% CI 0.63-1.07 for miscarriage rate). Cycles with low D3 cell number (five cells or fewer) had significantly higher miscarriage rate (9.2% versus 7.6%, aOR 1.33, 95% CI 1.02-1.75) compared with cycles with eight cells on D3. CONCLUSIONS: Poor-quality cleavage embryos should be cultivated to the blastocyst stage because high-quality blastocysts derived from poor-grade D3 embryos had acceptable pregnancy outcomes. When the blastocyst grade is identical, choosing embryos with higher D3 cell number (eight or more cells) for transfer could reduce the risk of early miscarriage.

The effect of gonadotrophin-releasing hormone agonist versus human chorionic gonadotrophin trigger on pregnancy and neonatal outcomes in Letrozole-HMG IUI cycles.

BACKGROUND: GnRHa and hCG are both used for oocyte maturation and ovulation triggering. However, GnRHa have a shorter half-life than hCG, which leads to luteal phase deficiency. Letrozole (LE) has been found to improve the luteal function. Thus, the choice of triggering strategy can be different in intrauterine insemination (IUI) cycles using LE and human menopausal gonadotropin (HMG). The aim of this study was to compare the pregnancy and neonatal outcomes of patients triggered with GnRHa versus hCG versus dual trigger in LE-IUI cycles. METHODS: This retrospective cohort study included 6,075 LE-HMG IUI cycles between January 2010 and May 2021 at a tertiary-care academic medical center in China. All cycles were divided into three groups according to different trigger strategies as hCG trigger group, GnRHa trigger group and dual trigger group. The primary outcome was clinical pregnancy rate. Logistic regression analysis was performed to explore other risk factors for clinical pregnancy rate. RESULTS: No significant difference was observed in clinical pregnancy rate between hCG, GnRHa and dual trigger cycles in LE-HMG IUI cycles (P = 0.964). The miscarriage rate was significantly lower in the GnRHa trigger group, and higher in the dual trigger group, compared with the hCG group (P = 0.045). Logistic analysis confirmed that triggering strategy was associated with miscarriage (aOR:0.427, 95%CI: 0.183-0.996, P = 0.049; aOR:0.298, 95%CI: 0.128-0.693, P = 0.005). No significant differences were observed regarding neonatal outcomes between the three groups. CONCLUSIONS: Our findings suggested that both GnRHa and dual trigger can be used to trigger ovulation in LE-HMG IUI cycles, but dual trigger must be used with caution.

Heterozygous loss-of-function variants in LHX8 cause female infertility characterized by oocyte maturation arrest.

PURPOSE: The genetic causes of oocyte maturation arrest leading to female infertility are largely unknown, and no population-based genetic analysis has been applied in cohorts of patients with infertility. We aimed to identify novel pathogenic genes causing oocyte maturation arrest by using a gene-based burden test. METHODS: Through comparison of exome sequencing data from 716 females with infertility characterized by oocyte maturation arrest and 3539 controls, we performed a gene-based burden test and identified a novel pathogenic gene LHX8. Splicing event was evaluated using a minigene assay, expression of LHX8 protein was assessed in HeLa cells, and nuclear subcellular localization was determined in both HeLa cells and mouse oocytes. RESULTS: A total of 5 heterozygous loss-of-function LHX8 variants were identified from 6 independent families (c.389+1G>T, c.412C>T [p.Arg138∗], c.282C>A [p.Cys94∗]; c.257dup [p.Tyr86∗]; and c.180del, [p.Ser61Profs∗30]). All the identified variants in LHX8 produced truncated LHX8 protein and resulted in loss of LHX8 nuclear localization in both HeLa cells and mouse oocytes. CONCLUSION: By combining genetic evidence and functional evaluations, we identified a novel pathogenic gene LHX8 and established the causative relationship between LHX8 haploinsufficiency and female infertility characterized by oocyte maturation arrest.

Changes in sexual frequency among 51 150 infertile Chinese couples over the past 10 years.

STUDY QUESTION: How did the sexual frequency change and what are the related influencing factors among infertile Chinese couples over the past 10 years? SUMMARY ANSWER: Sexual frequency has declined among infertile Chinese couples over the past decade, with such declines being most pronounced for women between the ages of 18 and 39. WHAT IS KNOWN ALREADY: Many researchers have explored trends in coital frequency and variables associated among healthy individuals in other nations. There have been major changes in all aspects of Chinese life and society over the past decade, including two major fertility policy adjustments. The sexual habits of infertile couples in China remain poorly understood and warrant further investigation. STUDY DESIGN, SIZE, DURATION: A retrospective cohort study of 51 150 infertile couples that visited our facility between January 2011 and December 2020 at a tertiary care academic medical centre. PARTICIPANTS/MATERIALS, SETTING, METHODS: The primary outcome for this study was whether couples had engaged in sexual intercourse ≤4 times/month or >4 times/month. Multivariable logistic regression analyses were performed to detect the association between the variables and sexual frequency. Analyses were further performed to determine whether observed trends remained evident in women from different age subgroups. To assess whether these trends differed before and after the introduction of the universal two-child policy in China (January 2016), we additionally assessed trends in these age subgroups of women relative to the time at which this policy was introduced. MAIN RESULTS AND THE ROLE OF CHANCE: The proportion of couples reporting having engaged in sexual intercourse >4 times/month fell over the past decade from 62.7% (2011-2013) to 55.9% (2014-2015) to 52.7% (2016-2020). Declines in sexual frequency were evident for women between the ages of 18 and 39 (P < 0.05), whereas no such changes were evident for women between the ages of 40 and 50. Younger men and women, as well as individuals with a less than junior college education level, reported higher frequencies of sexual intercourse. For women, being remarried and having a more recent diagnosis of infertility were associated with increased coital frequency. This frequency decreased progressively for women as BMI values increased. There was no detected relationship between coital frequency and nationality or history of prior births. LIMITATIONS, REASONS FOR CAUTION: These analyses were dependent on self-reported data, and may thus have been impacted by the over- or under-reporting of sexual frequency as a consequence of social desirability bias. In addition, not all potentially relevant variables were assessed in all analyses, and certain potentially relevant variables such as family income or pornography use were not measured in any analyses. WIDER IMPLICATIONS OF THE FINDINGS: Sexual frequency is closely related to infertility risks. This general downward trend in sexual frequency may warrant concern. At present, these reductions remain an interesting yet unexplained topic worthy of further study. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by the National Key Research and Development Program of China (Grant no. 2018YFC1003000) and the National Natural Science Foundation of China (Grant no. 81771533). The authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Impact of uterine malformations on pregnancy and neonatal outcomes of IVF/ICSI-frozen embryo transfer.

STUDY QUESTION: What is the impact of uterine malformations on reproductive and neonatal outcomes of IVF/ICSI-frozen embryo transfer? SUMMARY ANSWER: Unification defective uteri are associated with poorer neonatal outcomes including higher preterm delivery rate and lower birthweight, and septate uteri are associated with worse fertility outcomes including higher miscarriage and lower live birth rates (LBRs). WHAT IS KNOWN ALREADY: Several studies have investigated the negative effects of uterine malformations on pregnancy outcomes. However, an all-round and definitive conclusion has not been reached yet owing to the relatively low incidence of the disease and the heterogeneity of study populations, especially among women undergoing ART. STUDY DESIGN, SIZE, DURATION: This was a retrospective cohort study including 411 women with congenital uterine anomalies and 14 936 women with a normal uterus who underwent first frozen-thawed embryo transfer cycles of IVF/ICSI from July 2008 to August 2019. We compared reproductive outcomes. PARTICIPANTS/MATERIALS, SETTING, METHODS: Reproductive outcomes of women with uterine malformations were studied through three propensity score-matched comparisons (patients with bicorporeal uterus, septate uterus and hemi-uterus [bicorporeal, septate and hemi-uterus groups, respectively] along with corresponding control groups without uterine malformations). We also compared pregnancy and neonatal outcomes, and performed subgroup analysis addressing didelphus, bicornuate uteri and septate uteri before and after surgery independently. MAIN RESULTS AND THE ROLE OF CHANCE: Compared to the matched control group, women with a bicorporeal uterus had a significantly lower LBR (24.4% versus 34.8%, odds ratio (OR) 0.61 [95% CI: 0.37, 1.00], P = 0.048). The incidence of miscarriage and preterm delivery was higher but not statistically significant (29.0% versus 18.1%, OR 1.85 [95% CI: 0.82, 4.19], P = 0.135; 22.6% versus 9.9%, OR 2.64 [95% CI: 1.07, 6.52], P = 0.063, respectively). In addition, the bicorporeal group had a significantly lower gestational age, higher caesarean rate and lower birthweight than bicorporeal control. Women with a septate uterus had comparable clinical pregnancy rates to controls (43.3% versus 49.9%, OR 0.77 [95% CI: 0.57, 1.04], P = 0.091), increased miscarriage rates (23.5% versus 13.0%, OR 2.05 [95% CI: 1.18, 3.58], P = 0.010) and lower LBRs (29.4% versus 42.2%, OR 0.57 [95% CI: 0.41, 0.79], P = 0.001). In both singleton and twins pregnancies, pregnancy and neonatal outcomes were comparable between women with a septate uterus and control. Women with a hemi-uterus had a tendency for lower clinical pregnancy rate (36.8% versus 42.3%, OR 0.80 [95% CI: 0.52, 1.21], P = 0.287) and LBR (29.8% versus 33.1%, OR 0.86 [95% CI: 0.55, 1.34], P = 0.502), compared to women without malformations. The incidences of miscarriage and preterm delivery, respectively, were 16.7% versus 16.6% (OR 1.01 [95% CI: 0.41, 2.47], P = 0.989), and 9.5% versus 11.4% (OR 0.82 [95% CI: 0.27, 2.51], P = 1) in women with a hemi-uterus as compared to control. LIMITATIONS, REASONS FOR CAUTION: This was a single-centre, retrospective study in which neonatal data were extracted from parental questionnaires. The information on uteri septum type and surgery methods was poorly presented, with limited detail. In patients with uterine malformations, the number of babies with birth defects and twin pregnancies was relatively small, limiting the power of the study. WIDER IMPLICATIONS OF THE FINDINGS: Compared to patients with a normal uterus, women with uterine malformation have poorer reproductive outcomes. Pregnant women with a uterine anomaly need to be managed as high-risk pregnancies and followed with appropriate obstetric review. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the National Ministry of Technology (2018YFC1003000), the Elite Team Project of Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine (JY201801), Shanghai Sailing Program (21YF1423200) and the Fundamental Research Program Funding of Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine (JYZZ117). B.W.M. is supported by an NHMRC Investigatorgrant (GNT1176437). B.W.M. reports consultancy (with stock options) for ObsEva. B.W.M. has received research funding from Ferring and Merck. The authors declare no other competing interests. TRIAL REGISTRATION NUMBER: N/A.

Bi-allelic variants in KCNU1 cause impaired acrosome reactions and male infertility.

STUDY QUESTION: Are there new genetic factors responsible for male infertility with normal sperm quantity and morphology? SUMMARY ANSWER: We identified the bi-allelic variants in KCNU1 and confirmed it a novel pathogenetic gene for male infertility mainly due to impaired sperm acrosome reactions (ARs). WHAT IS KNOWN ALREADY: Until now, the underlying genetic determinants for male affected individuals exhibiting normal sperm quantity and morphology have been largely unknown. Potassium/calcium-activated channel subfamily U member 1 (KCNU1) is a sperm-specific potassium channel. The Kcnu1 null mutation in male mice causes infertility due to the impaired progressive motility and AR. STUDY DESIGN, SIZE, DURATION: We recruited a cohort of 126 male infertility individuals with typical asthenospermia or fertilization failure and focused on two infertile males from two consanguineous families from 2015 to 2020; whole-exome sequencing and homozygosity mapping were performed. We identified a homozygous missense variant (c.2144A>G, p.His715Arg) and a homozygous donor splice-site variant (c.1295 + 3A>C, p.Val405Glyfs*8) in KCNU1. Then, we generated a knock-in (KI) mouse model in September 2020 and have now carried out functional studies and possible treatment strategies. PARTICIPANTS/MATERIALS, SETTING, METHODS: The affected individuals with infertility were recruited from the Shanghai Ninth Hospital affiliated to Shanghai Jiao Tong University. Genomic DNA from the affected individual was extracted from peripheral blood. Whole-exome sequencing, homozygosity mapping and in silico analyses were used to screen and identify KCNU1 variants, and the variants were confirmed by Sanger sequencing. We used C57BL/6N mouse to construct KI mouse model to mimic the reproductive phenotype in vivo. We performed functional experiments by western blotting, AR assay and immunofluorescent Staining. Finally, we performed IVF and ICSI to explore the treatment strategies. MAIN RESULTS AND THE ROLE OF CHANCE: We identified a homozygous missense variant (c.2144A>G, p.His715Arg) and a homozygous donor splice-site variant (c.1295 + 3A>C, p.Val405Glyfs*8) in KCNU1 in two infertile males. We demonstrated that the splice-site variant affected normal alternative splicing of KCNU1, thus leading to the loss of function of KCNU1. Meanwhile, the missense pathogenic variant reduced the KCNU1 protein levels in sperm of both the affected individual and the KI mouse model, resulting in impaired ARs and male infertility. Intracytoplasmic sperm injection was able to rescue the deficiencies. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: The exact molecular mechanism of KCNU1 and pathways need to be further explore in the future. WIDER IMPLICATIONS OF THE FINDINGS: This is the first report that establishes a causal relationship between KCNU1 deficiency and male infertility, confirming the critical role of KCNU1 in human reproduction. Our findings expand our knowledge of the genes that play critical roles in the human sperm AR and provide a new genetic marker for infertility. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the SHIPM-pi fund no. JY201801 from the Shanghai Institute of Precision Medicine, Ninth People's Hospital Shanghai Jiao Tong University School of Medicine, the National Natural Science Foundation of China (81725006, 81771649, 81822019, 81771581, 81971450, 81971382, 82001538 and 82071642). The authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Effect of previous wedge resection for interstitial pregnancy on pregnancy and neonatal outcomes following frozen-thawed embryo transfer (FET) cycles of IVF/ICSI: a retrospective study.

OBJECTIVE: The present study aimed to evaluate pregnancy and neonatal outcomes in women, with a previous history of wedge resection for interstitial pregnancy, in frozen-thawed embryo transfer (FET) cycles of IVF/ICSI. METHODS: The present study involved a retrospective case-control assessment of 75 cases and 375 control subjects over 6 years in a single center. To compare pregnancy and neonatal outcomes between cases, treated using wedge resection, and controls without any previous history of ectopic pregnancy, propensity score matching (1:5) was utilized. The study also compared subgroups in the case group. RESULTS: Women with previous wedge resection exhibited higher rates of ectopic pregnancy and uterine rupture rate as compared to control subjects (9.1% vs 1.3%, P = 0.025 and 4.5% vs 0%, P = 0.035, respectively). No statistically significant differences were recorded between the two cohorts with regard to clinical pregnancy rate, live birth rate, and neonatal outcomes. For pregnancy type subgroup analysis, Z-score and rates of large for gestational age were recorded to be significantly lower in twin pregnancy subgroup when compared with singleton pregnancy subgroup (0.10 (- 0.59, 0.25) vs 0.50 (- 0.97, 1.39), P = 0.005; 4.5% vs 26.1%, P = 0.047, respectively). CONCLUSION: The results of the present study indicated that previous wedge resection correlated to a higher risk of ectopic pregnancy and uterine rupture. However, it might not be related to an increased risk of adverse neonatal outcomes. The study recommended cesarean section in these patients. Further studies are required to verify the validity of current recommendations.

A follow-up study on congenital anomalies in 2208 offspring of three years old born after luteal-phase stimulation.

RESEARCH QUESTION: What is the long-term safety in terms of congenital anomalies of a luteal-phase stimulation (LPS) protocol? DESIGN: In this cohort study, 664 couples and their children born after LPS and 1308 couples and their children born after a short agonist protocol were recruited. To investigate the long-term safety of LPS in terms of the prevalence of congenital anomalies, the physical growth and the health status of the offspring, the follow-up was divided into three steps: preparations before follow-up, first-stage follow-up including four telephone interviews, and second-stage follow-up when the children were aged 3 years. RESULTS: The total prevalence of congenital anomalies did not differ between groups. The detailed classification showed a significantly lower percentage of musculoskeletal system congenital anomalies in singletons (P = 0.020) and an obviously higher percentage of digestive system congenital anomalies in multiple births (P = 0.028), both in the LPS group. In the evaluation of physical growth and health status, no significant differences were discovered between the two groups. CONCLUSIONS: This study showed that offspring born after the LPS protocol did not exhibit an elevated rate of total congenital anomalies up to the age of 3. In addition, indicators regarding physical growth and health status were broadly similar between the two groups. These results have preliminarily confirmed the long-term safety of LPS. A subsequent long-term follow-up with a larger sample size should be carried out to generate more convincing evidence and more accurate conclusions.

Cumulative live birth rates for low-prognosis women over 5 years or 9 frozen-thawed embryo transfer cycles.

BACKGROUND: For heterogeneous populations of low-prognosis women, it remains unclear as to how long individuals should continue undergoing ART when attempting to have a baby, as there have been insufficient studies to date tracking the cumulative live birth rates (CLBRs) for these women over the entire course of their ART treatment, particularly over extended time periods. METHODS: This was a retrospective analysis of 17,698 women at a tertiary care academic medical center who had begun undergoing IVI/ICSI cycles using a progestin-primed ovarian stimulation (PPOS) approach between January 2013 and January 2019. Low-prognosis patients were stratified into four groups based upon POSEIDON criteria, with patients exhibiting normal or high ovarian reserves and response to stimulation (defined as AFC ≥5, > 9 oocytes retrieved) being included as controls (group 5). The CLBR within 5 years or 9 FET cycles from the ovum pick-up (OPU) day of the first cycle was the primary endpoint for this study, including all repetitive oocyte retrieval cycles and subsequent FET cycles. Optimistic and conservative approaches were used for the analysis of CLBRs and the depiction of cumulative incidence curves. RESULTS: Under both optimistic and conservative model analyses, normal and good responders exhibited the highest CLBR within 5 years or 9 FET cycles, followed by younger unexpected poor responders, younger expected poor responders, older unexpected poor responders, and older expected poor responders. Upward trends in CLBRs were evident across the five groups with the prolongation of time or an increase in FET cycle counts. Within the first 2 years or 3 FET cycles, the CLBRs rose rapidly, followed by more moderate increases over the following 2-3.5 years or 4-6 cycles, with expected poor responders exhibiting the most obvious improvements. All Patients reached a CLBR plateau after 3.5 years or 6 FET cycles. CONCLUSIONS: All low-prognosis women should undergo ART treatment for a minimum of 2 years or 3 FET cycles, and exhibit better outcomes when extending ART treatment to 3.5 years or 6 FET cycles (particularly for POSEIDON groups 3 and 4), but should consider ceasing further treatment thereafter due to a lack of apparent benefit.

Ptk2b deletion improves mice folliculogenesis and fecundity via inhibiting follicle loss mediated by Erk pathway.

Ptk2b has been found playing critical roles in oocyte maturation and subsequent fertilization in vitro. But what is the exact in vivo function in reproduction still elusive. Here, by constructing Ptk2b mutant mice, we found Ptk2b was not essential for mice fertility, unexpectedly, contrary to previously reported in vitro findings, we found Ptk2b ablation significantly improved female fecundity. Follicle counting indicated that the number of primordial follicles and growing follicles in matured mice was significantly increased in the absence of Ptk2b, whereas the primordial follicle formation showed no defects. We also found this regulation was in an autophosphorylation independent pathway, as autophosphorylation site mutant mice (PTK2BY402F ) show no phenotype in female fertility. Further biochemistry studies revealed that Ptk2b ablation promotes folliculogenesis via Erk pathway mediate follicle survival. Together, we found a novel biological function of Ptk2b in folliculogenesis, which could be potentially used as a therapeutic target for corresponding infertility.