The oocyte microenvironment is altered in adolescents compared to oocyte donors.

Study question: Are the molecular signatures of cumulus cells (CCs) and follicular fluid (FF) of adolescents undergoing fertility preservation differ from that of reproductively adult oocyte donors? Summary answer: The microenvironment immediately surrounding the oocyte, including the CCs and FF, is altered in adolescents undergoing fertility preservation compared to oocyte donors. What is known already: Adolescents experience a period of subfecundity following menarche. Recent evidence suggests that this may be at least partially due to increased oocyte aneuploidy. Reproductive juvenescence in mammals is associated with suboptimal oocyte quality. Study design size duration: This was a prospective cohort study. Adolescents (10-19 years old, N=23) and oocyte donors (22-30 years old, N=31) undergoing ovarian stimulation and oocyte retrieval at the Northwestern Fertility and Reproductive Medicine Center between November 1, 2020 and May 1, 2023 were enrolled in this study. Participants/materials setting methods: Patient demographics, ovarian stimulation, and oocyte retrieval outcomes were collected for all participants. The transcriptome of CCs associated with mature oocytes was compared between adolescents (10-19 years old, n=19), and oocyte donors (22-30 years old, n=19) using bulk RNA-sequencing. FF cytokine profiles (10-19 years old, n=18 vs. 25-30 years old, n=16) were compared using cytokine arrays. Main results and the role of chance: RNA-seq analysis revealed 581 differentially expressed genes (DEGs) in cumulus cells of adolescents relative to oocyte donors, with 361 genes downregulated and 220 upregulated. Genes enriched in pathways involved in cell cycle and cell division (e.g., GO:1903047, p= 3.5 × 10-43; GO:0051983, p= 4.1 × 10-30; GO:0000281, p= 7.7 × 10-15; GO:0044839, p= 5.3 × 10-13) were significantly downregulated, while genes enriched in several pathways involved in cellular and vesicle organization (e.g., GO:0010256, p= 1.2 × 10-8; GO:0051129, p= 6.8 × 10-7; GO:0016050, p= 7.4 × 10-7; GO:0051640, p= 8.1 × 10-7) were upregulated in CCs of adolescents compared to oocyte donors. The levels of 9 cytokines were significantly increased in FF of adolescents compared to oocyte donors: IL-1 alpha (2-fold), IL-1 beta (1.7-fold), I-309 (2-fold), IL-15 (1.6-fold), TARC (1.9-fold), TPO (2.1-fold), IGFBP-4 (2-fold), IL-12-p40 (1.7-fold) and ENA-78 (1.4-fold). Interestingly, 7 of these cytokines have known pro-inflammatory roles. Importantly, neither the CC transcriptomes or FF cytokine profiles were different in adolescents with or without cancer. Large scale data: Original high-throughput sequencing data will be deposited in Gene Expression Omnibus (GEO) before publication, and the GEO accession number will be provided here. Limitations reasons for caution: This study aims to gain insights into the associated gamete quality by studying the immediate oocyte microenvironment. The direct study of oocytes is more challenging due to sample scarcity, as they are cryopreserved for future use, but will provide a more accurate assessment of oocyte reproductive potential. Wider implications of the findings: Understanding the underpinnings of altered immediate oocyte microenvironment of adolescent patients may provide insights into the reproductive potential of the associated gametes in the younger end of the age spectrum. This has implications for the fertility preservation cycles for very young patients. Study funding/competing interests: This project was supported by Friends of Prentice organization SP0061324 (M.M.L and E.B.), Gesualdo Family Foundation (Research Scholar: M.M.L.), and NIH/NICHD K12 HD050121 (E.B.). The authors have declared that no conflict of interest exists.

Phthalates are detected in the follicular fluid of adolescents and oocyte donors with associated changes in the cumulus cell transcriptome.

Purpose: To investigate follicular fluid (FF) phthalate levels in adolescents undergoing fertility preservation compared to oocyte donors and explore its association with ovarian reserve and cumulus cell gene expression. Methods: 20 Adolescents (16.7 ± 0.6 years old) and 24 oocyte donors (26.2 ± 0.4 years old) undergoing fertility preservation were included in the study. Patient demographics, ovarian stimulation and oocyte retrieval outcomes were analyzed for each group. FF levels of 9 phthalate metabolites were assessed individually and as molar sums representative of common compounds (all phthalates: ΣPhthalates; DEHP: ΣDEHP), exposure sources (plastics: ΣPlastic; personal care products: ΣPCP), and modes of action (anti-androgenic: ΣAA) and compared between the two groups. Results: Follicular fluid ΣPlastic and ΣPCP levels were significantly higher in adolescents compared to oocyte donors (p<0.05). Follicular fluid ΣDEHP, ΣPlastic, ΣPCP, ΣAA, and ΣPhthalates levels were positively associated with antral follicle count (AFC) (p<0.05) in oocyte donors when adjusted for age, BMI, and race/ethnicity. RNA-seq analysis revealed 248 differentially expressed genes (DEGs) in cumulus cells of adolescents within the top quartile (n=4) of FF ΣPhthalates levels compared to the adolescents within the bottom half (n=9). Genes enriched in pathways involved in cell motility and development were significantly downregulated. Conclusion: Adolescents undergoing fertility preservation cycles demonstrate higher levels of phthalate metabolites in their follicular fluid compared to oocyte donors. Phthalate metabolite levels in FF are associated with higher AFC levels in oocyte donors. Higher phthalate levels in FF are associated with alterations in the cumulus cells transcriptome in adolescents.

Shear wave elastography to assess stiffness of the human ovary and other reproductive tissues across the reproductive lifespan in health and disease†.

The ovary is one of the first organs to show overt signs of aging in the human body, and ovarian aging is associated with a loss of gamete quality and quantity. The age-dependent decline in ovarian function contributes to infertility and an altered endocrine milieu, which has ramifications for overall health. The aging ovarian microenvironment becomes fibro-inflammatory and stiff with age, and this has implications for ovarian physiology and pathology, including follicle growth, gamete quality, ovulation dynamics, and ovarian cancer. Thus, developing a non-invasive tool to measure and monitor the stiffness of the human ovary would represent a major advance for female reproductive health and longevity. Shear wave elastography is a quantitative ultrasound imaging method for evaluation of soft tissue stiffness. Shear wave elastography has been used clinically in assessment of liver fibrosis and characterization of tendinopathies and various neoplasms in thyroid, breast, prostate, and lymph nodes as a non-invasive diagnostic and prognostic tool. In this study, we review the underlying principles of shear wave elastography and its current clinical uses outside the reproductive tract as well as its successful application of shear wave elastography to reproductive tissues, including the uterus and cervix. We also describe an emerging use of this technology in evaluation of human ovarian stiffness via transvaginal ultrasound. Establishing ovarian stiffness as a clinical biomarker of ovarian aging may have implications for predicting the ovarian reserve and outcomes of Assisted Reproductive Technologies as well as for the assessment of the efficacy of emerging therapeutics to extend reproductive longevity. This parameter may also have broad relevance in other conditions where ovarian stiffness and fibrosis may be implicated, such as polycystic ovarian syndrome, late off target effects of chemotherapy and radiation, premature ovarian insufficiency, conditions of differences of sexual development, and ovarian cancer. Summary sentence:  Shear Wave Elastography is a non-invasive technique to study human tissue stiffness, and here we review its clinical applications and implications for reproductive health and disease.

Cumulus expansion is impaired with advanced reproductive age due to loss of matrix integrity and reduced hyaluronan.

Reproductive aging is associated with ovulatory defects. Age-related ovarian fibrosis partially contributes to this phenotype as short-term treatment with anti-fibrotic compounds improves ovulation in reproductively old mice. However, age-dependent changes that are intrinsic to the follicle may also be relevant. In this study, we used a mouse model to demonstrate that reproductive aging is associated with impaired cumulus expansion which is accompanied by altered morphokinetic behavior of cumulus cells as assessed by time-lapse microscopy. The extracellular matrix integrity of expanded cumulus-oocyte complexes is compromised with advanced age as evidenced by increased penetration of fluorescent nanoparticles in a particle exclusion assay and larger open spaces on scanning electron microscopy. Reduced hyaluronan (HA) levels, decreased expression of genes encoding HA-associated proteins (e.g., Ptx3 and Tnfaip6), and increased expression of inflammatory genes and matrix metalloproteinases underlie this loss of matrix integrity. Importantly, HA levels are decreased with age in follicular fluid of women, indicative of conserved reproductive aging mechanisms. These findings provide novel mechanistic insights into how defects in cumulus expansion contribute to age-related infertility and may serve as a target to extend reproductive longevity.

Intrauterine Insemination After Human Chorionic Gonadotropin Trigger or Luteinizing Hormone Surge: A Meta-analysis.

OBJECTIVE: To assess the odds of pregnancy after intrauterine insemination (IUI) timed by ultrasound monitoring and human chorionic gonadotropin (hCG) administration compared with monitoring luteinizing hormone (LH) levels. DATA SOURCES: We searched PubMed (MEDLINE), EMBASE (Elsevier), Scopus (Elsevier), Web of Science (Clarivate Analytics), ClinicalTrials.gov (National Institutes of Health), and the Cochrane Library (Wiley) from the inception until October 1, 2022. No language limitations were applied. METHODS OF STUDY SELECTION: After deduplication, 3,607 unique citations were subjected to blinded independent review by three investigators. Thirteen studies (five retrospective cohort, four cross-sectional, two randomized controlled trials, and two randomized crossover studies) that enrolled women undergoing natural cycle, oral medication (clomid or letrozole), or both for IUI were included in the final random-effects model meta-analysis. Methodologic quality of included studies was assessed with the Downs and Black checklist. TABULATION, INTEGRATION, AND RESULTS: Data extraction was compiled by two authors, including publication information, hCG and LH monitoring guidelines, and pregnancy outcomes. No significant difference in odds of pregnancy between hCG administration and endogenous LH monitoring was observed (odds ratio [OR] 0.92, 95% CI 0.69-1.22, P =.53). Subgroup analysis of the five studies that included natural cycle IUI outcomes also showed no significant difference in odds of pregnancy between the two methods (OR 0.88, 95% CI 0.46-1.69, P =.61). Finally, a subgroup analysis of 10 studies that included women who underwent ovarian stimulation with oral medications (clomid or letrozole) did not demonstrate a difference in odds of pregnancy between ultrasonography with hCG trigger and LH-timed IUI (OR 0.88, 95% CI 0.66-1.16, P =.32). Statistically significant heterogeneity was noted between studies. CONCLUSION: This meta-analysis showed no difference between pregnancy outcomes between at-home LH monitoring and timed IUI. SYSTEMATIC REVIEW REGISTRATION: PROSPERO, CRD42021230520.

Common mechanisms of physiological and pathological rupture events in biology: novel insights into mammalian ovulation and beyond.

Ovulation is a cyclical biological rupture event fundamental to fertilisation and endocrine function. During this process, the somatic support cells that surround the germ cell undergo a remodelling process that culminates in breakdown of the follicle wall and release of a mature egg. Ovulation is driven by known proteolytic and inflammatory pathways as well as structural alterations to the follicle vasculature and the fluid-filled antral cavity. Ovulation is one of several types of systematic remodelling that occur in the human body that can be described as rupture. Although ovulation is a physiological form of rupture, other types of rupture occur in the human body which can be pathological, physiological, or both. In this review, we use intracranial aneurysms and chorioamniotic membrane rupture as examples of rupture events that are pathological or both pathological and physiological, respectively, and compare these to the rupture process central to ovulation. Specifically, we compared existing transcriptomic profiles, immune cell functions, vascular modifications, and biomechanical forces to identify common processes that are conserved between rupture events. In our transcriptomic analysis, we found 12 differentially expressed genes in common among two different ovulation data sets and one intracranial aneurysm data set. We also found three genes that were differentially expressed in common for both ovulation data sets and one chorioamniotic membrane rupture data set. Combining analysis of all three data sets identified two genes (Angptl4 and Pfkfb4) that were upregulated across rupture systems. Some of the identified genes, such as Rgs2, Adam8, and Lox, have been characterised in multiple rupture contexts, including ovulation. Others, such as Glul, Baz1a, and Ddx3x, have not yet been characterised in the context of ovulation and warrant further investigation as potential novel regulators. We also identified overlapping functions of mast cells, macrophages, and T cells in the process of rupture. Each of these rupture systems share local vasoconstriction around the rupture site, smooth muscle contractions away from the site of rupture, and fluid shear forces that initially increase and then decrease to predispose one specific region to rupture. Experimental techniques developed to study these structural and biomechanical changes that underlie rupture, such as patient-derived microfluidic models and spatiotemporal transcriptomic analyses, have not yet been comprehensively translated to the study of ovulation. Review of the existing knowledge, transcriptomic data, and experimental techniques from studies of rupture in other biological systems yields a better understanding of the physiology of ovulation and identifies avenues for novel studies of ovulation with techniques and targets from the study of vascular biology and parturition.

Morphokinetic parameters of mouse oocyte meiotic maturation and cumulus expansion are not affected by reproductive age or ploidy status.

INTRODUCTION: Morphokinetic analysis using a closed time-lapse monitoring system (EmbryoScope + ™) provides quantitative metrics of meiotic progression and cumulus expansion. The goal of this study was to use a physiologic aging mouse model, in which egg aneuploidy levels increase, to determine whether there are age-dependent differences in morphokinetic parameters of oocyte maturation. METHODS: Denuded oocytes and intact cumulus-oocyte complexes (COCs) were isolated from reproductively young and old mice and in vitro matured in the EmbryoScope + ™. Morphokinetic parameters of meiotic progression and cumulus expansion were evaluated, compared between reproductively young and old mice, and correlated with egg ploidy status. RESULTS: Oocytes from reproductively old mice were smaller than young counterparts in terms of GV area (446.42 ± 4.15 vs. 416.79 ± 5.24 µm2, p < 0.0001) and oocyte area (4195.71 ± 33.10 vs. 4081.62 ± 41.04 µm2, p < 0.05). In addition, the aneuploidy incidence was higher in eggs with advanced reproductive age (24-27% vs. 8-9%, p < 0.05). There were no differences in the morphokinetic parameters of oocyte maturation between oocytes from reproductively young and old mice with respect to time to germinal vesicle breakdown (GVBD) (1.03 ± 0.03 vs. 1.01 ± 0.04 h), polar body extrusion (PBE) (8.56 ± 0.11 vs. 8.52 ± 0.15 h), duration of meiosis I (7.58 ± 0.10 vs. 7.48 ± 0.11 h), and kinetics of cumulus expansion (0.093 ± 0.002 vs. 0.089 ± 0.003 µm/min). All morphokinetic parameters of oocyte maturation were similar between euploid and aneuploid eggs irrespective of age. CONCLUSION: There is no association between age or ploidy and the morphokinetics of mouse oocyte in vitro maturation (IVM). Future studies are needed to evaluate whether there is an association between morphokinetic dynamics of mouse IVM and embryo developmental competence.

Ovarian volume partially explains associations of phthalate biomarkers with anti-Müllerian hormone and estradiol in midlife women.

BACKGROUND/OBJECTIVES: Women are ubiquitously exposed to endocrine disruptors, including phthalates. Ovarian follicles undergoing folliculogenesis (indirectly measured by ovarian volume) produce anti-Müllerian hormone (AMH) and estradiol (E2). We evaluated associations of phthalates with ovarian volume to assess whether this explained prior positive associations of phthalates with AMH and E2. METHODS: Women ages 45-54 years (n = 614) had transvaginal ultrasounds of right/left ovaries to calculate mean ovarian volume. Women provided up-to-four urine and blood samples for quantifying AMH (first serum sample), E2 (all serum samples), and nine phthalate metabolites (from pooled urine, representing six parent phthalates). Multivariable linear or logistic regression models (for individual phthalate biomarkers), as well as weighted quantile sum (WQS) regression (for mixture analyses) evaluated associations of phthalate biomarkers with ovarian volume. Using cross-sectional mediation analysis, we assessed whether associations of phthalates with ovarian volume partially explained those of phthalates with AMH or E2. RESULTS: Most women were non-Hispanic White (68%) and pre-menopausal (67%) with higher urinary phthalate metabolite concentrations than U.S. women. In single-pollutant models, 10% increases in mono(3-carboxypropyl) phthalate (MCPP) and monobenzyl phthalate (MBzP) were associated with 0.44% (95% CI: -0.02%, 0.91%) and 0.62% (95% CI: 0.02%, 1.23%) larger ovarian volumes, respectively. As a cumulative mixture, 10% increases in the phthalate mixture were associated with 2.89% larger ovarian volume (95%CI: 0.27, 5.59) with MCPP (35%) and MBzP (41%) identified as major contributors. Higher ovarian volume due to a 10% increase in MBzP (indirect effect OR: 1.004; 95% CI: 1.00, 1.01) explained 16% of the positive association between MBzP and higher AMH, whereas higher ovarian volume due to a 10% increase in MCPP (indirect effect %Δ: 0.11; 95% CI: -0.01, 0.22) explained 23% of the positive association between MCPP and E2. CONCLUSION: In this cross-sectional study, phthalates were associated with increased ovarian volume, with implications for midlife hormone production.

Follicle isolation methods reveal plasticity of granulosa cell steroidogenic capacity during mouse in vitro follicle growth.

Follicles are the functional unit of the ovary and several methods have been developed to grow follicles ex vivo, which recapitulate key events of oogenesis and folliculogenesis. Enzymatic digestion protocols are often used to increase the yield of follicles from the ovary. However, the impact of these protocols on the outermost theca and granulosa cells, and thereby follicle function, is not well defined. To investigate the impact of enzymatic digestion on follicle function, we collected preantral follicles from CD1 mice either by enzymatic digestion (Enzy-FL) or mechanical isolation (Mech-FL) and compared follicle growth, steroidogenesis and cell differentiation within an encapsulated in vitro follicle growth system which maintains the 3D architecture of the oocyte and its surrounding somatic cells. Follicles were encapsulated in 0.5% alginate and cultured for 8 days. Compared with Enzy-FL, Mech-FL grew more rapidly and produced significantly higher levels of androstenedione, estradiol and progesterone. The expression of theca-interstitial cell marker genes, Cyp17a1, which encodes 17-hydroxylase/17, 20-lyase and catalyzes the hydroxylation of pregnenolone and progesterone to 17-hydroxypregnenolone and 17-hydroxyprogesterone, and the conversion of these products into dehydroepiandrosterone and androstenedione, and Star, which encodes a transport protein essential for cholesterol entry into mitochondria, were also higher in Mech-FL than in Enzy-FL. Mech-FL maintained an intact theca-interstitial layer on the outer edge of the follicle that phenocopied in vivo patterns as confirmed by alkaline phosphatase staining, whereas theca-interstitial cells were absent from Enzy-FL from the onset of culture. Therefore, preservation of the theca cell layer at the onset of culture better supports follicle growth and function. Interestingly, granulosa cells in the outermost layers of Enzy-FL expressed CYP17A1 by Day 4 of culture while maintaining inhibin α-subunit expression and a cuboidal nucleus. Thus, in the absence of theca-interstitial cells, granulosa cells have the potential to differentiate into androgen-producing cells. This work may have implications for human follicle culture, where enzymatic isolation is required owing to the density of the ovarian cortex.

Quantitative morphokinetic parameters identify novel dynamics of oocyte meiotic maturation and cumulus expansion†.

Meiotic maturation and cumulus expansion are essential for the generation of a developmentally competent gamete, and both processes can be recapitulated in vitro. We used a closed time-lapse incubator (EmbryoScope+™) to establish morphokinetic parameters of meiotic progression and cumulus expansion in mice and correlated these outcomes with egg ploidy. The average time to germinal vesicle breakdown (GVBD), time to first polar body extrusion (PBE), and duration of meiosis I were 0.91 ± 0.01, 8.82 ± 0.06, and 7.93 ± 0.06 h, respectively. The overall rate of cumulus layer expansion was 0.091 ± 0.002 µm/min, and the velocity of expansion peaked during the first 8 h of in vitro maturation (IVM) and then slowed. IVM of oocytes exposed to Nocodazole, a microtubule disrupting agent, and cumulus oocyte complexes (COCs) to 4-methylumbelliferone, a hyaluronan synthesis inhibitor, resulted in a dose-dependent perturbation of morphokinetics, thereby validating the system. The incidence of euploidy following IVM was >90% for both denuded oocytes and intact COCs. No differences were observed between euploid and aneuploid eggs with respect to time to GVBD (0.90 ± 0.22 vs. 0.97 ± 0.19 h), time to PBE (8.89 ± 0.98 vs. 9.10 ± 1.42 h), duration of meiosis I (8.01 ± 0.91 vs. 8.13 ± 1.38 h), and overall rate and kinetics of cumulus expansion (0.089 ± 0.02 vs 0.088 ± 0.03 µm/min) (P > 0.05). These morphokinetic parameters provide novel quantitative and non-invasive metrics for the evaluation of meiotic maturation and cumulus expansion and will enable screening compounds that modulate these processes.

Fertility Preservation During the COVID-19 Pandemic: Modified But Uncompromised.

Purpose: Throughout COVID-19, our clinic remained operational for patients requiring urgent fertility preservation (FP). This study aimed to characterize changes to clinical protocols during the first wave of COVID-19 and compare outcomes to historical controls. Methods: We performed a retrospective cohort study at a university fertility center examining all patients who underwent medically indicated FP cycles during the American Society for Reproductive Medicine (ASRM) COVID-19 Task Force-recommended suspension of fertility treatment (March 17-May 11, 2020) and patients from the same time period in 2019. FP care was modified for safety during the first wave of COVID-19 with fewer monitoring visits and infection control measures. FP cycle characteristics and outcomes were compared across years. Results: The volume of cycles was nearly 30% higher in 2020 versus 2019 (27 vs. 19). Diagnoses, age, and anti-Mullerian hormone were similar between cohorts. More patients elected to pursue embryo cryopreservation over oocyte cryopreservation in 2020 versus 2019 (45.8% vs. 5.2%, p < 0.005). Patients managed during COVID-19 had fewer monitoring visits (5 ± 1 vs. 6 ± 1, p = 0.02), and 37.5% of cycles utilized a blind trigger injection. There was no difference in total days of ovarian stimulation (11 ± 1 vs. 11 ± 2, p > 0.05), but 2020 cycles utilized more gonadotropin (4770 ± 1480 vs. 3846 ± 1438, p = 0.04). There was no difference in total oocytes retrieved (19 ± 14 vs. 22 ± 12, p > 0.05) or mature oocytes vitrified (15 ± 12 vs. 17 ± 9, p > 0.05) per cycle. Conclusions: FP continued during COVID-19, and more cycles were completed in 2020 versus 2019. Despite minimized monitoring, outcomes were optimal and equivalent to historical controls, suggesting FP care can be adapted without compromising outcomes.

Age-associated changes in cumulus cells and follicular fluid: the local oocyte microenvironment as a determinant of gamete quality.

The ovary is the first organ to age in humans with functional decline evident already in women in their early 30s. Reproductive aging is characterized by a decrease in oocyte quantity and quality, which is associated with an increase in infertility, spontaneous abortions, and birth defects. Reproductive aging also has implications for overall health due to decreased endocrinological output. Understanding the mechanisms underlying reproductive aging has significant societal implications as women globally are delaying childbearing and medical interventions have greatly increased the interval between menopause and total lifespan. Age-related changes inherent to the female gamete are well-characterized and include defects in chromosome and mitochondria structure, function, and regulation. More recently, it has been appreciated that the extra-follicular ovarian environment may have important direct or indirect impacts on the developing gamete, and age-dependent changes include increased fibrosis, inflammation, stiffness, and oxidative damage. The cumulus cells and follicular fluid that directly surround the oocyte during its final growth phase within the antral follicle represent additional critical local microenvironments. Here we systematically review the literature and evaluate the studies that investigated the age-related changes in cumulus cells and follicular fluid. Our findings demonstrate unique genetic, epigenetic, transcriptomic, and proteomic changes with associated metabolomic alterations, redox status imbalance, and increased apoptosis in the local oocyte microenvironment. We propose a model of how these changes interact, which may explain the rapid decline in gamete quality with age. We also review the limitations of published studies and highlight future research frontiers.

Immature Follicular Origins and Disrupted Oocyte Growth Pathways Contribute to Decreased Gamete Quality During Reproductive Juvenescence in Mice.

Egg quality dictates fertility outcomes, and although there is a well-documented decline with advanced reproductive age, how it changes during puberty is less understood. Such knowledge is critical, since advances in Assisted Reproductive Technologies are enabling pre- and peri-pubertal patients to preserve fertility in the medical setting. Therefore, we investigated egg quality parameters in a mouse model of the pubertal transition or juvenescence (postnatal day; PND 11-40). Animal weight, vaginal opening, serum inhibin B levels, oocyte yield, oocyte diameter, and zona pellucida thickness increased with age. After PND 15, there was an age-associated ability of oocytes to resume meiosis and reach metaphase of meiosis II (MII) following in vitro maturation (IVM). However, eggs from the younger cohort (PND 16-20) had significantly more chromosome configuration abnormalities relative to the older cohorts and many were at telophase I instead of MII, indicative of a cell cycle delay. Oocytes from the youngest mouse cohorts originated from the smallest antral follicles with the fewest cumulus layers per oocyte, suggesting a more developmentally immature state. RNA Seq analysis of oocytes from mice at distinct ages revealed that the genes involved in cellular growth signaling pathways (PI3K, mTOR, and Hippo) were consistently repressed with meiotic competence, whereas genes involved in cellular communication were upregulated in oocytes with age. Taken together, these data demonstrate that gametes harvested during the pubertal transition have low meiotic maturation potential and derive from immature follicular origins.

Menstruation: science and society.

Women's health concerns are generally underrepresented in basic and translational research, but reproductive health in particular has been hampered by a lack of understanding of basic uterine and menstrual physiology. Menstrual health is an integral part of overall health because between menarche and menopause, most women menstruate. Yet for tens of millions of women around the world, menstruation regularly and often catastrophically disrupts their physical, mental, and social well-being. Enhancing our understanding of the underlying phenomena involved in menstruation, abnormal uterine bleeding, and other menstruation-related disorders will move us closer to the goal of personalized care. Furthermore, a deeper mechanistic understanding of menstruation-a fast, scarless healing process in healthy individuals-will likely yield insights into a myriad of other diseases involving regulation of vascular function locally and systemically. We also recognize that many women now delay pregnancy and that there is an increasing desire for fertility and uterine preservation. In September 2018, the Gynecologic Health and Disease Branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development convened a 2-day meeting, "Menstruation: Science and Society" with an aim to "identify gaps and opportunities in menstruation science and to raise awareness of the need for more research in this field." Experts in fields ranging from the evolutionary role of menstruation to basic endometrial biology (including omic analysis of the endometrium, stem cells and tissue engineering of the endometrium, endometrial microbiome, and abnormal uterine bleeding and fibroids) and translational medicine (imaging and sampling modalities, patient-focused analysis of menstrual disorders including abnormal uterine bleeding, smart technologies or applications and mobile health platforms) to societal challenges in health literacy and dissemination frameworks across different economic and cultural landscapes shared current state-of-the-art and future vision, incorporating the patient voice at the launch of the meeting. Here, we provide an enhanced meeting report with extensive up-to-date (as of submission) context, capturing the spectrum from how the basic processes of menstruation commence in response to progesterone withdrawal, through the role of tissue-resident and circulating stem and progenitor cells in monthly regeneration-and current gaps in knowledge on how dysregulation leads to abnormal uterine bleeding and other menstruation-related disorders such as adenomyosis, endometriosis, and fibroids-to the clinical challenges in diagnostics, treatment, and patient and societal education. We conclude with an overview of how the global agenda concerning menstruation, and specifically menstrual health and hygiene, are gaining momentum, ranging from increasing investment in addressing menstruation-related barriers facing girls in schools in low- to middle-income countries to the more recent "menstrual equity" and "period poverty" movements spreading across high-income countries.

Baseline Endometrial Thickness or Endometrial Thickness Change in Response to Estrogen Is Not Predictive of Frozen Embryo Transfer Success in Medicated Cycles.

There is some consensus that endometrial thickness (EMT) needs to be at least 7 mm on day of embryo transfer. However, the predictive role of baseline EMT and EMT change in response to estrogen is largely unknown. The objective of this study was to evaluate the role of endometrial thickness in frozen embryo transfer (FET) cycles. We analyzed the association of baseline endometrial thickness (EMTb-Day 3 of cycle) and endometrial thickness change (EMTΔ-from baseline to start of progesterone supplementation) with FET success in 121 cycles. We also investigated whether baseline estradiol levels and body mass index (BMI) are associated with EMTb. No difference was observed in EMTb and EMTΔ in cycles resulting in clinical pregnancy compared to unsuccessful transfers (5.1 ± 2.2 mm vs 5.0 ± 1.9 mm; p = 0.92, and 4.7 ± 2.4 mm vs. 4.4 ± 2.4 mm; p = 0.56). When 7 mm cut-off was used, endometrial thickness on the day of start of progesterone supplementation (EMTp) was also not different between groups (9.8 ± 2.9 mm vs. 9.4 ± 2.5 mm; p = 0.50). Multivariable logistic regression models did not demonstrate any predictive value of EMTb, EMTp, or EMTΔ in predicting success of FET cycles (p = 0.92, p = 0.80, and p = 0.84, respectively). There was no significant correlation between EMTb and baseline estradiol levels (r = -0.001; p = 0.985). BMI showed statistically significant weak positive linear relationship with EMTb (r = +0.29; p = 0.002). Our study did not demonstrate any significant relationship between baseline endometrial thickness or endometrial thickness change and clinical pregnancy rates in frozen embryo transfer cycles. Significant positive linear relationship of BMI with baseline endometrial thickness, despite no correlation between baseline estradiol and EMTb, points to the role of possible other mechanism affecting EMT besides estradiol in obese patients.

Embryo through the lens: from time-lapse cinematography to artificial intelligence.

"Once a new technology rolls over you, if you're not part of the steamroller, you're part of the road." -Stewart Brand.