Posthemithyroidectomy hypothyroidism. Prevalence and predictive markers. Comparison between patients with euthyroid and hyperthyroid nodular goitre.

BACKGROUND AND OBJECTIVE: Posthemithyroidectomy hypothyroidism (PHH) is a relatively common complication (22%-30%) for which we have no published information from our country. The objective of the study is to determine the prevalence of PHH and evaluate its predictive markers by comparing patients who had euthyroidism with those who had hyperthyroidism before hemithyroidectomy. PATIENTS AND METHOD: Retrospective observational cross-sectional study on 106 patients, 88 euthyroid before hemithyroidectomy and 18 hyperthyroid. RESULTS: Prevalence of PHH in euthyroid patients 42% (89.2% subclinical hypothyroidism; 10.8% manifest hypothyroidism) and in hyperthyroid patients 50% (77.8% subclinical hypothyroidism; 22.2% manifest hypothyroidism). Predictive markers in euthyroid patients: preoperative thyrotropin ≥ 2.2 mIU/L (OR: 4.278, 95% CI: 1.689-10.833; sensitivity: 54.1%, 95% CI: 38%-70.1%; specificity: 78.4%, 95% CI: 67.1%-89.7%), age ≥50 years (OR: 3.509, 95% CI: 1.438-8.563; sensitivity: 64.9%, 95% CI: 49.5%-80.3%; specificity: 64.7%, 95% CI: 51.6%-77.8%) and percentage of remainder lobe ≤ 19.6% (OR: 1.024, 95%: 1.002-1.046; sensitivity: 70.2%, 95% CI: 55.5%-84.9%; specificity: 48.6%, 95% CI: 34.9%-62.3%). Predictive marker in hyperthyroid patients: weight >70 kg (OR: 28, 95% CI: 2.067-379.247; sensitivity: 88.9%, 95% CI: 68.4%-100%; specificity: 88.9%, 95% CI: 68.4%-100%). CONCLUSIONS: This is the first study in our country that demonstrates a prevalence of PHH above the average in euthyroid patients, which is slightly higher and more intense in hyperthyroid patients, and that recognizes the classic predictive markers in euthyroid patients but highlights a novel predictive marker marker in hyperthyroid patients, useful to assess a different risk of PHH when indicating hemithyroidectomy and to establish closer control of postoperative hormonal evolution.

The cellular basis of feeding-dependent body size plasticity in sea anemones.

Many animals share a lifelong capacity to adapt their growth rates and body sizes to changing environmental food supplies. However, the cellular and molecular basis underlying this plasticity remains only poorly understood. We therefore studied how the sea anemones Nematostella vectensis and Aiptasia (Exaiptasia pallida) respond to feeding and starvation. Combining quantifications of body size and cell numbers with mathematical modelling, we observed that growth and shrinkage rates in Nematostella are exponential, stereotypic and accompanied by dramatic changes in cell numbers. Notably, shrinkage rates, but not growth rates, are independent of body size. In the facultatively symbiotic Aiptasia, we show that growth and cell proliferation rates are dependent on the symbiotic state. On a cellular level, we found that >7% of all cells in Nematostella juveniles reversibly shift between S/G2/M and G1/G0 cell cycle phases when fed or starved, respectively. Furthermore, we demonstrate that polyp growth and cell proliferation are dependent on TOR signalling during feeding. Altogether, we provide a benchmark and resource for further investigating the nutritional regulation of body plasticity on multiple scales using the genetic toolkit available for Nematostella.

Culture time to optimize embryo cell-free DNA analysis for frozen-thawed blastocysts undergoing noninvasive preimplantation genetic testing for aneuploidy.

OBJECTIVE: To investigate the ideal time in culture to optimize embryo cell-free deoxyribonucleic acid (cfDNA) analysis in frozen-thawed blastocysts undergoing noninvasive preimplantation genetic testing for aneuploidy (PGT-A). Cell-free DNA is released into the spent blastocyst media (spent media) by the embryo. However, the optimal timing to determine maximal cfDNA in the case of frozen-thawed blastocysts undergoing noninvasive PGT-A remains to be elucidated. DESIGN: In this prospective observational study, 135 spent media and corresponding whole blastocysts were collected from January 2021 through March 2022. SETTING: Private fertility clinics. PATIENTS: Day-5 frozen-thawed blastocysts were cultured for 8 hours (Day-5 Short) or 24 hours (Day-5 Long), whereas day-6 frozen-thawed blastocysts were cultured for 8 hours (Day-6 Short). The spent media and whole blastocysts were then collected for further analysis. Spent media and whole blastocysts were amplified using whole genome amplification and sequenced using next-generation sequencing. MAIN OUTCOME MEASURES: Informativity and concordance rates between cfDNA in spent media and whole blastocyst DNA were compared according to the different times in culture. RESULTS: When comparing time in culture, informativity rates for spent media were significantly higher for Day-5 Long and Day-6 Short (>91%) compared with the Day-5 Short group (<60%). A similar trend was observed for cases with and without a previous PGT-A. Regarding blastocyst expansion grade, informativity rates were lower on Day-5 Short compared with Day-5 Long and Day-6 Short, regardless of expansion degree. This decrease was significant for Gardner-grade expansion grades 3, 4, and 5-6. In addition, for a similar time in culture, the grade of expansion did not have an impact on the informativity rates. For concordance rates, no significant differences were observed among the 3 groups. In all cases, concordance rates were 90.5% for Day-5 Short, 93.6% for Day-5 Long, and 92.3% for Day-6 Short. No impact of the expansion grade was observed on concordance rates. CONCLUSION: Noninvasive PGT-A in frozen-thawed blastocysts yields very high concordance rates with whole blastocysts, possibly limiting the need for invasive PGT-A and making it available for a wider range of patients.

Bispectral index monitoring for sedation in scheduled adult colonoscopy: A randomized controlled trial.

BACKGROUND: Patients should be closely monitored during procedures under sedation outside the operating room, but it is unclear which type of monitoring is best. We investigated the efficacy and safety of BIS monitoring vs conventional monitoring for sedation during colonoscopy. METHODS: We performed a double-blind clinical trial in 180 patients undergoing elective colonoscopy. Patients were randomized to 1) the BIS group or 2) a control group, in which sedation was monitored with a BIS monitor or the Ramsay Sedation Score, respectively. The primary outcome was the rate of sedation-induced adverse events in both groups. Secondary outcomes were the characteristics of patients who developed adverse events, and time during colonoscopy when these events occurred, propofol and remifentanil dosage, and patient satisfaction. RESULTS: Univariate analysis showed fewer cardiopulmonary complications in the BIS group (41.11% vs 57.78% in controls; p = 0.02). Multivariate analysis found a significantly higher risk of adverse events in older patients (95% CI, 1.013-1.091; p = 0.0087) and in men (95% CI, 1.129-7.668; p = 0.0272). These events were observed at the hepatic flexure. No significant differences between propofol or remifentanil dosage, use of rescue medication, and patient satisfaction were observed between groups. CONCLUSIONS: Our data suggest that BIS monitoring during sedation in scheduled colonoscopies reduces adverse respiratory events. Although its routine use in sedation does not appear to be warranted, clinicians should take steps to identify patients with a higher risk of complications who might benefit from this type of monitoring.

Interactions of Opuntia ficus-indica with Dactylopius coccus and D. opuntiae (Hemiptera: Dactylopiidae) through the Study of Their Volatile Compounds.

Opuntia ficus-indica has always interacted with many phytophagous insects; two of them are Dactylopius coccus and D. opuntiae. Fine cochineal (D. coccus) is produced to extract carminic acid, and D. opuntiae, or wild cochineal, is an invasive pest of O. ficus-indica in more than 20 countries around the world. Despite the economic and environmental relevance of this cactus, D. opuntiae, and D. coccus, there are few studies that have explored volatile organic compounds (VOCs) derived from the plant-insect interaction. The aim of this work was to determine the VOCs produced by D. coccus and D. opuntiae and to identify different VOCs in cladodes infested by each Dactylopius species. The VOCs (essential oils) were obtained by hydrodistillation and identified by GC-MS. A total of 66 VOCs from both Dactylopius species were identified, and 125 from the Esmeralda and Rojo Pelón cultivars infested by D. coccus and D. opuntiae, respectively, were determined. Differential VOC production due to infestation by each Dactylopius species was also found. Some changes in methyl salicylate, terpenes such as linalool, or the alcohol p-vinylguaiacol were related to Dactylopius feeding on the cladodes of their respective cultivars. Changes in these VOCs and their probable role in plant defense mechanisms should receive more attention because this knowledge could improve D. coccus rearing or its inclusion in breeding programs for D. opuntiae control in regions where it is a key pest of O. ficus-indica.

Suicidio más allá del diagnóstico: un enfoque centrado en la persona y su circunstancia / Suicide Beyond Diagnosis: A Person and Their Circumstances-Centered Approach

Existe una pluralidad de enfoques sobre el suicidio. En la literatura científica y en el ámbito sanitario es hegemónico el modelo biomédico. En este trabajo se presen-ta un modelo alternativo, existencial-contextual, de estudio, comprensión, prevención y posvención del suicidio en el ámbito sanitario. El trabajo se divide en dos partes. La primera expone los tres elementos esenciales del modelo existencial-contextual: la no-ción de persona, el concepto de problemas de la vida y la práctica de la relación de cui-dado y acompañamiento. La segunda desarrolla algunas de las diferencias asistenciales más importantes entre el modelo biomédico y el existencial-contextual del suicidio. Se concluye en la necesidad de superar el paradigma suicidológico biomédico tradicional y construir un espacio amplio transdisciplinar de reflexión suicidológica crítica a la altura de nuestro tiempo. Este cambio de paradigma requiere pasar de una lógica que prioriza lo patológico-biológico-farmacológico a otra socio-psico-política del suicidio que integre las aportaciones del modelo biomédico sin reducirse a ellas. (AU)

There is a plurality of understanding approaches to suicide. In the scientific literature and the healthcare field, the biomedical model is hegemonic. This paper pre-sents an alternative existential-contextual model for the study, understanding, preven-tion and postvention of suicide in the healthcare field. The academic paper is divided into two parts. The first part sets out the three essential elements of the existential-contex-tual model: the notion of personhood, the concept of life problems and the practice of caring and supportive relationships. The second one develops some of the most impor-tant differences in care between the biomedical and the existential-contextual models of suicide. It concludes with the need to overcome the traditional biomedical suicidological paradigm and to build a broad transdisciplinary space for critical suicidological reflection that is up to date with our times. This paradigm shift requires moving from a logic that prioritizes the pathological-biological-pharmacological to a socio-psycho-political logic of suicide that integrates the contributions of the biomedical model without being reduced to them. (AU)

Normocalcemic hyperparathyroidism after successful parathyroidectomy for single parathyroid adenoma: Prevalence, etiological factors, predictive markers, treatment and evolution.

BACKGROUND AND OBJECTIVE: Postparathyroidectomy normocalcemic hyperparathyroidism (PPNCHPPT) is a frequent situation for which we have no information in our country. The objective is to know our prevalence of PPNCHPPT, the associated etiological factors, the predictive markers, the treatment administered and the evolution. PATIENTS AND METHOD: Retrospective observational cross-sectional study on 42 patients. Twelve patients with PPNCHPPT and 30 without PPNCHPPT are compared. RESULTS: HPPTNCPP prevalence: 28.6%. Etiological factors: vitamin D deficiency: 75%; bone remineralization: 16.7%; renal failure: 16.7%; hypercalciruria: 8.3%. No change in the set point of calcium-mediated parathormone (PTH) secretion was observed, but an increase in the preoperative PTH/albumin-corrected calcium (ACC) ratio was observed. Predictive markers: PTH/ACC ratio (AUC 0.947; sensitivity 100%, specificity 78.9%) and PTH (AUC 0.914; sensitivity 100%, specificity 73.7%) one week postparathyroidectomy. EVOLUTION: follow-up 30 ±â€¯16.3 months: 50% normalized PTH and 8.3% had recurrence of hyperparathyroidism. Patients with PPNCHPPT less frequently received preoperative treatment with bisphosphonates and postoperative treatment with calcium salts. CONCLUSIONS: This is the first study in our country that demonstrates a mean prevalence of PPNCHPPT, mainly related to a vitamin D deficiency and a probable resistance to the action of PTH, which can be predicted by the PTH/ACC ratio and PTH a week post-intervention and often evolves normalizing the PTH. We disagree with the etiological effect of hypercalciuria and the change in the PTH/calcemia regulation set point, and we acknowledge the scant treatment administered with calcium salts in the postoperative period.

Human embryo live imaging reveals nuclear DNA shedding during blastocyst expansion and biopsy.

Proper preimplantation development is essential to assemble a blastocyst capable of implantation. Live imaging has uncovered major events driving early development in mouse embryos; yet, studies in humans have been limited by restrictions on genetic manipulation and lack of imaging approaches. We have overcome this barrier by combining fluorescent dyes with live imaging to reveal the dynamics of chromosome segregation, compaction, polarization, blastocyst formation, and hatching in the human embryo. We also show that blastocyst expansion mechanically constrains trophectoderm cells, causing nuclear budding and DNA shedding into the cytoplasm. Furthermore, cells with lower perinuclear keratin levels are more prone to undergo DNA loss. Moreover, applying trophectoderm biopsy, a mechanical procedure performed clinically for genetic testing, increases DNA shedding. Thus, our work reveals distinct processes underlying human development compared with mouse and suggests that aneuploidies in human embryos may not only originate from chromosome segregation errors during mitosis but also from nuclear DNA shedding.

Effect of service experience, engagement and satisfaction on the future intentions of customers of a sports services.

This research proposes a management model for a sports centre, through the variables of customer experience, satisfaction, engagement and its influence on the loyalty of its users. This work is carried out with the aim of providing sports managers with information that will enable them to improve the viability of their service. A sample of 378 customers of the sports service was used, 208 men and 170 women from a private sports centre. First, the psychometric properties of the scales used were obtained by means of a confirmatory factor analysis (CFA), followed by an analysis of their reliability and validity, and then the model fit was established using structural equations. Finally, the Sobel test was used to determine whether user satisfaction was mediated. Significant direct relationships between the constructs were found to exist, as well as an indirect effect of satisfaction within the model analysed. This model presented a goodness of fit, as well as the reliability analyses of the scales presented results supported by the literature. The results of this research demonstrate the mediating effect of satisfaction on the relationship between service experiences and customers' future commitment and intentions. It is important to know the experiences of customers through the sports service as it allows managers to develop precise strategies and actions to improve these experiences and raise the levels of commitment to the service, and consequently to strengthen the loyalty of customers for a long time.

Influence of Sports Participation on the Behaviors of Customers of Sports Services: Linear and Qualitative Comparative Analysis Models.

Sports services have become an important enclave for our society. Due to its complete sports offer, customers can perform physical activity that helps them to improve their health and well-being. In fitness centers, managers try to know what their customers are looking for in order to create more personalized experiences, as well as to improve their health. This study seeks to understand the influence that sports frequency has on the future behavior of users of a sports center, using two complementary methodologies. A sample of 383 users of a private sports center was used. The two complementary methodologies used were linear models and comparative qualitative analysis, based on the combination of sets. The results show how sports frequency influences the process of creating users' future behaviors. Considering that none of the variables are necessary, it is observed that perceived value has a significant influence on users' future behaviors. The use of two complementary methodologies provides a more complete understanding, which helps sports managers to plan and manage effectively to ensure user satisfaction and loyalty. In addition, facilities can incentivize customers through loyalty programs and promotions to maintain their engagement, as well as healthy styles to encourage service recommendations.

Cellular and environmental dynamics influence species-specific extents of organelle gene retention.

Mitochondria and plastids rely on many nuclear-encoded genes, but retain small subsets of the genes they need to function in their own organelle DNA (oDNA). Different species retain different numbers of oDNA genes, and the reasons for these differences are not completely understood. Here, we use a mathematical model to explore the hypothesis that the energetic demands imposed by an organism's changing environment influence how many oDNA genes it retains. The model couples the physical biology of cell processes of gene expression and transport to a supply-and-demand model for the environmental dynamics to which an organism is exposed. The trade-off between fulfilling metabolic and bioenergetic environmental demands, and retaining genetic integrity, is quantified for a generic gene encoded either in oDNA or in nuclear DNA. Species in environments with high-amplitude, intermediate-frequency oscillations are predicted to retain the most organelle genes, whereas those in less dynamic or noisy environments the fewest. We discuss support for, and insight from, these predictions with oDNA data across eukaryotic taxa, including high oDNA gene counts in sessile organisms exposed to day-night and intertidal oscillations (including plants and algae) and low counts in parasites and fungi.

Evaluation of an early detection protocol, intensive treatment and control of post-surgical hypoparathyroidism in the first month after total thyroidectomy.

BACKGROUND AND OBJECTIVE: Hypoparathyroidism is the most common complication of total thyroidectomy and usually requires monitoring of calcaemia, whereby it is one of the factors that most contributes to hospital stay. The objective of the study is to evaluate the clinical usefulness of the application of our protocol for early detection, intensive treatment and control of hypoparathyroidism in the first month after thyroidectomy. PATIENTS AND METHOD: Retrospective observational cross-sectional study of 79 patients who underwent total thyroidectomy in whom parathormone (PTH) and calcemia determinations were performed at 6-8 h and 18-24 h post-surgery. When the PTH value was lower than inferior limit of the reference (15 pg/ml), oral treatment was started with 1000 mg of calcium and 0.25 µg of calcitriol every 8 h followed by calcemia controls. RESULTS: Twenty-six cases (32.9%) of normocalcemic hypoparathyroidism were detected in whom treatment prevented their progression to hypocalcaemia, except for 3 cases that had an episode of mild asymptomatic hypocalcaemia. There were no cases of moderate/severe hypocalcaemia and only one case of asymptomatic mild hypercalcaemia. There were no readmissions due to calcium abnormalities. No case with PTH > 15 pg/ml had hypocalcaemia. The protocol allowed a hospital stay of 24 h. The prevalence of permanent hypoparathyroidism was 5.1%. CONCLUSIONS: The application of our protocol during the first month after thyroidectomy is very useful because it avoids the appearance of moderate/severe hypocalcaemia and hypercalcaemia, allows a short hospital stay and is associated with a low prevalence of permanent hypoparathyroidism.

Cell-free deoxyribonucleic acid analysis in preimplantation genetic testing.

Detection of chromosomal aneuploidies and monogenic disorders in preimplantation embryos is essential for selecting the best embryo for transfer during in vitro fertilization to achieve a healthy pregnancy. Preimplantation genetic testing (PGT) is typically performed on preimplantation embryos to select a genetically normal embryo for transfer. A trophectoderm biopsy is necessary for PGT; this is an invasive procedure to the embryo that requires specialized equipment and highly trained embryologists, resulting in high costs associated with in vitro fertilization treatment. Moreover, the biopsy procedure may increase the likelihood of developing pregnancy complications, such as preeclampsia and hypertensive disorders. Therefore, there is a need for noninvasive embryo screening strategies. The presence of cell-free deoxyribonucleic acid in the embryo culture medium presents an opportunity to screen for genetic abnormalities. Cell-free deoxyribonucleic acid is released by embryos in the latter stages of preimplantation development, and its analysis has been proposed as a noninvasive approach for PGT. Here, we review studies reporting the concordance rates between cell-free deoxyribonucleic acid and trophectoderm biopsies, or whole blastocysts, in couples undergoing PGT. Noninvasive PGT results are promising for aneuploidy detection, with some early evidence of successful clinical application. Further research is required to explore its application for the detection of structural rearrangements and monogenic disorders.

Promoting Physical Activity Habits after Completing Secondary School: Does the Age Matter?

Physical inactivity is one of the most important problems in our society, especially during adolescence. During this stage of schooling, students practice physical activity in physical education classes, but after they finish school, many of them stop practicing it. This research aims to determine which variables predict the intention to practice physical activity after finishing secondary school and to discover the effect that age during adolescence has on these predictive variables. A questionnaire was administered to a sample of secondary school students. The results show that physical exercise identity influences the three antecedents of this theory, while the attitude towards the behaviour (ß = 0.13; p < 0.05), perceived behavioural control (ß = 0.46; p < 0.05), and physical self-concept (ß = 0.41; p < 0.05), have a statistically significant influence on the intention to be physically active. Moreover, when the age is lower, is more important to develop a positive perceived behavioural control and physical exercise identity. Moreover, for younger male adolescents instead of the physical exercise itself, identity seems more important in developing a positive attitude towards behaviour. Likewise, in young female adolescents a low level of support from their close environment (subjective norm) leads to dropping out. The research concludes with the importance of including these variables in physical education classes to promote physical activity practice after completion of secondary school. Some practical implications are presented.

Clinical usefulness of thyroid ultrasonography in patients with primary hypothyroidism.

BACKGROUND AND OBJECTIVE: Despite the value of ultrasonography in the detection of chronic thyroiditis (CT) as well as in nodular goitre, it is often only indicated in patients with hypothyroidism if a palpable goitre or a thyroid mass is identified. The objective of the study is to evaluate the clinical usefulness of thyroid ultrasonography in patients with primary hypothyroidism without clinical suspicion of nodular goitre. And more specifically, to analyse its value in the aetiological diagnosis of hypothyroidism, and to evaluate its contribution in the detection and characterisation of coexisting subclinical thyroid nodular disease. PATIENTS AND METHOD: Prospective cross-sectional observational study of 114 patients with primary hypothyroidism of CT or idiopathic aetiology, without symptoms or cervical palpation suspected of nodular goitre, who underwent a thyroid function test, a serological study of antithyroid antibodies, a thyroid ultrasonound and, when appropriate, a cytological study of the nodules found. RESULTS: Ultrasonound allowed CT to be recognised as the cause of hypothyroidism in 19% of patients who had a negative serological study, and detected nodules larger than 9mm in 22 patients (16 with antithyroid antibodies). A cytological study was performed in 18 of the cases. Five patients underwent surgery, with carcinoma found in two of them. CONCLUSIONS: Thyroid ultrasound is useful in the aetiological diagnosis of primary hypothyroidism as well as in the detection of a coexisting, unsuspected, but clinically relevant nodular goitre, so this examination should be indicated in the initial study of patients with primary hypothyroidism.

Humoral and Cellular Immune Responses After a 3-dose Course of mRNA-1273 COVID-19 Vaccine in Kidney Transplant Recipients: A Prospective Cohort Study.

In kidney transplant recipients, there is discordance between the development of cellular and humoral response after vaccination against SARS-CoV-2. We sought to determine the interplay between the 2 arms of adaptive immunity in a 3-dose course of mRNA-1273 100 µg vaccine. Methods: Humoral (IgG/IgM) and cellular (N- and S-ELISpot) responses were studied in 117 kidney and 12 kidney-pancreas transplant recipients at the following time points: before the first dose, 14 d after the second dose' and before and after the third dose, with a median of 203 and 232 d after the start of the vaccination cycle, respectively. Results: After the second dose, 26.7% of naive cases experienced seroconversion. Before the third dose and in the absence of COVID-19, this percentage increased to 61.9%. After the third dose, seroconversion occurred in 80.0% of patients. Naive patients who had at any time point a detectable positivity for S-ELISpot were 75.2% of the population, whereas patients who maintained S-ELISpot positivity throughout the study were 34.3%. S-ELISpot positivity at 42 d was associated with final seroconversion (odds ratio' 3.14; 95% confidence interval' 1.10-8.96; P = 0.032). Final IgG titer was significantly higher in patients with constant S-ELISpot positivity (P < 0.001). Conclusions: A substantial proportion of kidney transplant recipients developed late seroconversion after 2 doses. Cellular immunity was associated with the development of a stronger humoral response.

Eye-Related COVID-19: A Bibliometric Analysis of the Scientific Production Indexed in Scopus.

This paper analyzes, from a bibliometric viewpoint, those publications that relate COVID-19 and eye indexed in Scopus since the beginning of the pandemic, and it identifies the resulting main research lines. A bibliographic search in the Scopus database was conducted for publications that simultaneously include ocular and visual manifestations and aspects with COVID-19, from 1 January 2020 to 16 March 2021, and the obtained bibliographic information was processed with VOSviewer (v. 1.6.16). A total of 2206 documents were retrieved, and 60% were original articles. The USA published the most studies (24.6%). The retrieved documents had a total of 18,634 citations. The h index of the set of retrieved documents was 58. The Indian Journal of Ophthalmology was the most productive journal, while JAMA Neurology and The Lancet accounted for 20% of citations. Three keyword clusters representing hotspots in this field were identified. Eye-related COVID-19 research is an emerging field with plenty of scientific evidence whose growth is expected to increase as the aspects and manifestations of the disease, its treatment and the effect of vaccination on it become known.

Non-invasive preimplantation genetic testing for aneuploidies: an update.

Aneuploidy is common among preimplantation human embryos used in assisted reproductive technology. Because abnormal chromosome number can negatively affect reproductive outcome, in-vitro-fertilized embryos routinely undergo aneuploidy testing before transfer into the uterus. This testing typically involves an invasive trophectoderm biopsy of a blastocyst-stage embryo. However, emerging evidence indicates that, during in-vitro development, embryos secrete cell-free DNA into their culture medium; this phenomenon suggests the potential for an alternative, non-invasive assay for aneuploidy. Embryonic cell-free DNA-based assays exhibit high concordance with trophectoderm biopsies, inner cell mass and the whole blastocyst. Yet informativity and concordance rates may be influenced by several factors: the culture day when the medium is collected, contamination with external and/or cumulus cell DNA, and previous manipulation of the embryos. This review discusses non-invasive embryonic cell-free DNA analysis as a biomarker to prioritize blastocysts for transfer to help increase implantation rates and reduce miscarriage rates and time to achieve pregnancy. Ongoing research on the mechanisms underlying embryonic cell-free DNA secretion and how this impacts its role as a biomarker of aneuploidy are also discussed.