Cairo consensus on the IVF laboratory environment and air quality: report of an expert meeting

Undisturbed culture: a clinical examination of this culture strategy on embryo in vitro development and clinical outcomes

OBJECTIVE

To compare the effect of a fully undisturbed culture strategy over a sequential one on embryo in vitro development and clinical outcomes in intracytoplasmic sperm injection (ICSI) cycles.

DESIGN

Retrospective cohort study.

SETTING

University-affiliated private IVF center.

PATIENT(S)

This study included 4,564 ICSI cycles performed over 5 years, including autologous and oocyte donation treatments with extended embryo culture until blastocyst in one of the two defined culture strategies.

INTERVENTION(S)

Embryo cohorts were cultured in one of two culture systems: a fully undisturbed culture, including an incubator with integrated time-lapse technology, a one-step culture medium and embryo selection assisted by semi-automatic tools on the basis of embryo morphokinetics, or a sequential culture, using a conventional benchtop incubator, sequential media and traditional morphological evaluation under optical microscope. The effect of the culture strategies on embryo development and clinical outcomes was quantified by generalized estimated equations, controlling for possible confounders through the inverse probability of the treatment weighting method.

MAIN OUTCOME MEASURE(S)

Weighted odds ratios (ORs) and 95% confidence intervals (CIs) for live birth rate after fresh single embryo transfer and the cumulative live birth rate. In addition, blastocyst development and morphology and other intermediate outcomes were also assessed.

RESULT(S)

A significant positive association was found between the employment of undisturbed embryo culture and higher live birth rate in the first embryo transfer in both autologous (OR, 1.617; 95% CI, 1.074-2.435) and oocyte donation cycles (OR, 1.316; 95% CI, 1.036-1.672). Cumulative live birth rate after 1-year follow-up was also positively associated with the undisturbed culture strategy in oocyte donation cycles (OR, 1.5; 95% CI, 1.179-1.909), but not in autologous cycles (OR, 1.051; 95% CI, 0.777-1.423). Similarly, blastocyst rate, good morphology blastocyst rate, and utilization rate were positively associated with the employment of undisturbed culture in oocyte donation cycles, but not in autologous cycles.

CONCLUSION(S)

These findings imply that a culture system combining integrated time-lapse incubators with a one-step culture medium may enhance the success rates of patients undergoing ICSI treatment by increasing the production of higher quality blastocysts and improving embryo selection while streamlining laboratory procedures and workflow.

Cairo Consensus on Accreditation as the Basis for Future-Proofing the ART Laboratory

An international consensus meeting was convened to discuss globally applicable strategies for 'future-proofing' ART laboratories. The central theme was how the application of the foundational principles of laboratory accreditation enables any centre to create an ethos and framework that will support future-proofing in all regards. Discussions focussed on ART laboratory services from egg retrieval and semen specimen receipt to embryo transfer, as well as pertinent cryobanking activities. Issues related to whether ART treatment should be considered an essential service, overall clinic operations, general patient care, and the provision of clinical treatment, were not included as they fall under the purview of physicians and public health authorities. This report details the 16 core consensus points reached, which are supported by extensive practical recommendations that cover the gamut of ART laboratory operations.

Disposables used cumulatively in routine IVF procedures could display toxicity

STUDY QUESTION

Is there a cumulative toxicity of disposables used in IVF procedures?

SUMMARY ANSWER

A toxicity may be detected when consumables are used cumulatively, while no toxicity is detected when the same consumables are used and tested individually.

WHAT IS KNOWN ALREADY

Many components of items used in IVF laboratories may impair human embryonic development. Consequently, it is necessary to screen all reagents and materials which could be in contact with gametes and embryos. Toxicity tests, such as the mouse embryo assay and the human sperm motility assay (HSMA), are used by manufacturers as quality control tools to demonstrate the safety of their products. This evaluation is currently individually performed for each single consumable. However, during an IVF cycle, several devices are used sequentially, potentially creating a cumulative exposure to chemical contaminants, which could not be detected for individually tested consumables.

STUDY DESIGN, SIZE, DURATION

The objective of this observational study conducted from March 2021 to October 2022 was to evaluate with the HSMA methodology if there was a cumulative toxicity when several disposables are sequentially used. Fourteen categories of consumables currently used in routine IVF procedures were studied, which included devices used for sperm and oocyte collection (cups, condoms, and oocyte aspiration needles), manipulation (flasks, tubes, tips, pipettes, embryo transfer catheters, syringes, and gloves), culture (dishes), and storage (straws).

PARTICIPANTS/MATERIALS, SETTING, METHODS

After obtaining patient consent, the surplus semen assessed as having normal parameters according to the World Health Organization 2010 criteria were used to perform the HSMAs. First, each consumable was tested individually. Then, associations of three, four, and five consumables, previously validated as non-toxic when tested individually, were analyzed. HSMAs were conducted three times to ensure reproducibility, with a defined toxicity threshold of a sperm motility index (SMI) below 0.85 in at least two of three tests.

MAIN RESULTS AND THE ROLE OF CHANCE

Thirty-six references of disposables were first individually tested across 53 lots. Forty-nine (92%) demonstrated compliance. However, four (8%) devices revealed toxicity: one lot of 1 ml syringes, two lots of sperm cups, and one lot of 25 cm2 flasks. These four references were excluded from the IVF routine procedures. A total of 48 combinations of consumables were assessed, involving 41 lots from 32 references that were previously individually tested. Among the evaluated combinations, 17 out of 48 (35%) associations exhibited toxicity with a SMI below 0.85 for two of the three tests (n = 8) or all the three tests (n = 9). Notably, three out of 17 (18%) of the three-consumable associations, five out of 16 (31%) of the four-consumable associations, and nine out of 15 (60%) of the five-consumable associations were found not compliant. The toxicity did not originate from a single consumable, because only consumables that were individually pre-validated as non-toxic were included in the combinations, but the toxicity had a cumulative origin. The risk of cumulative toxicity increased with the number of consumables included in the association (Cochran-Mantel-Haenszel statistic, P = 0.013).

LIMITATIONS, REASONS FOR CAUTION

The high proportion of non-compliant combinations of disposables can be attributed directly to the extreme rigorous extraction conditions employed during the tests, which could deviate from the conditions encountered in routine clinical use. Also, the methodology employed in the HSMAs (e.g. toxicity extraction duration, sperm concentrations, and protein supplementation of the medium) can influence the sensitivity of the tests.

WIDER IMPLICATIONS OF THE FINDINGS

This study highlights the significance of performing toxicity testing on devices before introducing them into clinical practice. Disposables should be tested individually to detect immediate toxicities and also in combination. Our results advocate rationalizing the number of consumables used in each IVF procedure and re-evaluating the use of glass consumables.

STUDY FUNDING/COMPETING INTEREST(S)

This study received fundings from GCS Ramsay Santé pour l'Enseignement et la Recherche (Paris, France) and the Centre de Biologie Médicale BIOGROUP (Le Chesnay-Rocquencourt, France). The authors declare that they have no conflict of interest that could be perceived as prejudicing the impartiality of the reported research.

TRIAL REGISTRATION NUMBER

N/A.

ASEBIR Quality Special Interest Group guidance for quality in assisted reproduction technology

Assisted human reproduction has undergone rapid advances since its inception 45 years ago. To keep pace with these advances, assisted reproduction laboratories should adhere to a quality management system that addresses staffing and training, physical space and air quality, equipment maintenance and other operational matters, and ensures gamete and embryo handling in accordance with the latest quality and safety standards. Accordingly, this review aims to provide a reference document that highlights the critical aspects to consider when establishing and operating an ART laboratory. The review collates and expands upon published national and international guidelines and consensus documents, providing easier access to this large body of important information.

Clinical Benefits of Decreased Photo-Oxidative Stress on Human Embryo Development

OBJECTIVE

Early embryonic development is characterized by rapid cell division and gene activation, making the embryo extremely sensitive to environmental influences. Light exposure can affect embryonic development through a direct toxic effect on the embryo via the generation of reactive oxygen species. In a previous study, we demonstrated the positive effect of improved light-protected embryo culture conditions implemented in our laboratory. This study aimed to investigate the changes in human embryo development under light protection during the conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

MATERIALS AND METHODS

We tested the potential beneficial effect of light filters to reduce the risk of toxic effects of light. IVF outcomes were compared between two experimental conditions, light protection with red light filters versus no light protection as a control.

RESULTS

Blastocyst development rate in IVF was significantly higher in the light-protected group than in the group treated under conventional conditions (46.6 vs. 26.7%). In the case of ICSI, we obtained a similar result (44.5 vs. 31.6%). The rate of cryopreservation with at least one embryo was higher in the light-protected phase (32.8%) than in the conventionally manipulated phase (26.8%). The abortion rate was also significantly lower during the light-protected period in IVF, resulting in a higher live birth rate.

CONCLUSIONS

The implementation of light protection to reduce the embryotoxic wavelengths of light in IVF centers may improve the blastocyst development rate and embryo quality while maintaining embryo safety.

Sustainability in the IVF laboratory: recommendations of an expert panel

The healthcare industry is a major contributor to greenhouse gas emissions. Assisted reproductive technology is part of the larger healthcare sector, with its own heavy carbon footprint. The social, economic and environmental costs of this collective carbon footprint are becoming clearer, as is the impact on human reproductive health. Alpha Scientists in Reproductive Medicine and the International IVF Initiative collaborated to seek and formulate practical recommendations for sustainability in IVF laboratories. An international panel of experts, enthusiasts and professionals in reproductive medicine, environmental science, architecture, biorepository and law convened to discuss the topics of importance to sustainability. Recommendations were issued on how to build a culture of sustainability in the workplace, implement green design and building, use life cycle analysis to determine the environmental impact, manage cryostorage more sustainably, and understand and manage laboratory waste with prevention as a primary goal. The panel explored whether the industry supporting IVF is sustainable. An example is provided to illustrate the application of green principles to an IVF laboratory through a certification programme. The UK legislative landscape surrounding sustainability is also discussed and a few recommendations on 'Green Conferencing' are offered.

The Internet of Things in assisted reproduction

The Internet of Things (IoT) is a network connecting physical objects with sensors, software and internet connectivity for data exchange. Integrating the IoT with medical devices shows promise in healthcare, particularly in IVF laboratories. By leveraging telecommunications, cybersecurity, data management and intelligent systems, the IoT can enable a data-driven laboratory with automation, improved conditions, personalized treatment and efficient workflows. The integration of 5G technology ensures fast and reliable connectivity for real-time data transmission, while blockchain technology secures patient data. Fog computing reduces latency and enables real-time analytics. Microelectromechanical systems enable wearable IoT and miniaturized monitoring devices for tracking IVF processes. However, challenges such as security risks and network issues must be addressed through cybersecurity measures and networking advancements. Clinical embryologists should maintain their expertise and knowledge for safety and oversight, even with IoT in the IVF laboratory.

Association between ambient air pollutants and birthweight of singletons following assisted reproductive technologies

OBJECTIVE

To investigate the associations between exposure to ambient air pollutants and birthweight following ART treatment.

DESIGN

Retrospective cohort study.

METHODS

We included 11,599 singletons derived from fresh cycles or frozen-thawed embryo transfer (FET) cycles between Jan 2013 and Dec 2019. Exposure to six air pollutants (SO2, NO2, CO, O3, PM2.5, and PM10) at patients` residences and the clinic site were estimated using the inverse distance weighting interpolation method based on data obtained from monitor sites. The daily mean levels of pollutants were estimated in potential exposure windows (the period from three months before treatment to oocyte retrieval, the period of ovarian stimulation, the period of in vitro culture, the period from embryo transfer to hCG test, the period of entire pregnancy, the 1st, 2nd, and 3rd trimester) were calculated. Generalized additive models adjusted for confounders including maternal age, BMI, and parity were used to evaluate the association between exposures and birthweight. Interaction of exposures and ART-associated factors, such as supraphysiologic estradiol and frozen-thawed, were explored in an XGboost model.

MAIN OUTCOME MEASURES

Birthweight and z-score of singletons.

RESULTS

In fresh cycles, O3 exposure during the period from three months before treatment to oocyte retrieval and SO2 exposure during in vitro culture at the ART clinic showed a linear association with birthweight (7.24, 95% CI: 1.18-13.31 g per 10 μg/m3 increase in O3; 25.92, 95% CI: 8.26-43.58 g per 10 μg/m3 increase in SO2, respectively). For patients receiving single blastocyst transfer with exposures below the China standard of 20 μg/m3, an increase of 10 μg/m3 in SO2 was associated with a 61.52 (95% CI: 1.13-121.91) g increase in birthweight. In FET cycles, no significant association was found between air pollution and birthweight. XGboost model did not reveal a strong interaction between the exposures and ART-related factors, except for the interactions between O3 exposure and BMI. However, none of the interactions reached a higher rank of importance.

CONCLUSIONS

Air pollution exposure during ART treatment may affect the birthweight of the offspring.

Cryostorage management of reproductive cells and tissues in ART: status, needs, opportunities and potential new challenges

Among the wide range of procedures performed by clinical embryologists, the cryopreservation of reproductive cells and tissues represents a fundamental task in the daily routine. Indeed, cryopreservation procedures can be considered a subspecialty of medically assisted reproductive technology (ART), having the same relevance as sperm injection or embryo biopsy for preimplantation genetic testing. However, although a great deal of care has been devoted to optimizing cryopreservation protocols, the same energy has only recently been spent on developing and implementing strategies for the safe and reliable storage and transport of reproductive specimens. Herein, we have summarized the content of the available guidelines, the risks, the needs and the future perspectives regarding the management of cryopreservation biorepositories used in ART.

Considerations on staffing levels for a modern assisted reproductive laboratory

The duties recently performed in the embryology laboratory have deeply increased compared to those realized a couple of decades ago. Currently, procedures include conventional in vitro fertilization (IVF) and ICSI techniques, or processing of surgically retrieved sperm, embryo culture and time-lapse monitoring, blastocyst culture, as well as trophectoderm biopsy for preimplantation genetic testing and cryopreservation. These techniques require not only time, but also high knowledge level and acutely concentration by the embryologist team. The existing data indicate that an IVF laboratory need to have adequate staffing levels to perform the required daily duties, and to work in optimal conditions that are critical to assure a high quality service, as well as avoiding incidents and to provide the best outcomes. As a result, IVF clinics have invested in human resources, but there is still a large discrepancy between IVF centres on the number of embryologists employed. Currently there is no golden standard on the human resource requirements for assisted reproductive technology procedures; therefore, in this review paper we aim to provide arguments to take into account to determine the embryology staffing requirements in an embryology laboratory to assure optimal safety and efficiency of operations.

Modelling the equilibrium partitioning of low concentrations of airborne volatile organic compounds in human IVF laboratories

RESEARCH QUESTION

Can volatile organic compounds (VOC) be modelled in an IVF clinical setting?

DESIGN

The study performed equilibrium modelling of low concentrations of airborne VOC partitioning from the air phase into the oil cover layer into the water-based culture media and into/onto the embryo (air-oil-water-embryo). The air-phase VOC were modelled based on reported VOC concentrations found in modern assisted reproductive technology (ART) suites, older IVF clinics, and hospitals, as well as at 10 parts per billion (ppb) and 100 ppb for all compounds. The modelling was performed with 23 documented healthcare-specific VOC.

RESULTS

Based on the partitioning model, seven compounds (acrolein, formaldehyde, phenol, toluene, acetaldehyde, ethanol and isopropanol) should be of great concern to the embryologist and clinician. Acrolein, formaldehyde, phenol, toluene and acetaldehyde are the VOC with the most potent cytotoxic factor and the highest toxic VOC concentration in media. In addition, ethanol and isopropanol are routinely found in the greatest air-phase concentrations and modelled to have the highest water-based culture concentrations.

CONCLUSIONS

The results of the equilibrium partitioning modelling of VOC provides a fundamental understanding of how airborne VOC partition from the air phase and negatively influence human IVF outcomes. The results presented here are based on the theoretical model and the values presented have not yet been measured in a laboratory or clinical setting. High air-phase concentrations and toxic concentrations of VOC in culture media are likely indicators of poor clinical outcomes. Based on this model, improved air quality in IVF laboratories reduces the chemical burden imparted on embryos, which supports findings of improved IVF outcomes with reduced air-phase VOC concentrations.

Effects of air pollution on clinical pregnancy rates after in vitro fertilisation (IVF): a retrospective cohort study

OBJECTIVE

To evaluate the effect of air pollution, from oocyte retrieval to embryo transfer, on the results of in vitro fertilisation (IVF) in terms of clinical pregnancy rates, at two fertility centres, from 2013 to 2019.

DESIGN

Exploratory retrospective cohort study.

SETTING

This retrospective cohort study was performed in the Reproductive Biology Department of Bordeaux University Hospital localised in Bordeaux, France and the Jean Villar Fertility Center localised in Bruges, France.

PARTICIPANTS

This study included 10 763 IVF attempts occurring between January 2013 and December 2019, 2194 of which resulted in a clinical pregnancy.

PRIMARY AND SECONDARY OUTCOME MEASURES

The outcome of the IVF attempt was recorded as the presence or absence of a clinical pregnancy; exposure to air pollution was assessed by calculating the cumulative exposure of suspended particulate matter, fine particulate matter, black carbon, nitrogen dioxide and ozone (O₃₎, over the period from oocyte retrieval to embryo transfer, together with secondary exposure due to the presence of the biomass boiler room, which was installed in 2016, close to the Bordeaux University Hospital laboratory. The association between air pollution and IVF outcome was evaluated by a random-effects logistic regression analysis.

RESULTS

We found negative associations between cumulative O₃ exposure and clinical pregnancy rate (OR=0.92, 95% CI = (0.86 to 0.98)), and between biomass boiler room exposure and clinical pregnancy rate (OR=0.75, 95% CI = (0.61 to 0.91)), after adjustment for potential confounders.

CONCLUSION

Air pollution could have a negative effect on assisted reproductive technology results and therefore precautions should be taken to minimise the impact of outdoor air on embryo culture.

Monozygotic twin rate among ART centers: a multicenter analysis of data from 18 Italian units

PURPOSE

The risk of monozygotic twins (MZTs) is increased in couples undergoing assisted reproductive technology (ART) treatments. Several systematic reviews have investigated the possible determinants linked to ART, but results obtained have not been conclusive. The study aims to investigate whether the incidence of MZT differed among ART centers.

METHODS

This is a multicenter retrospective cohort study using the Italian ART National Registry database and involving the centers reporting data from individual ART cycles from 2015 to 2019. To investigate the incidence of MZT, only single embryo transfer cycles were considered. Women who had sex-discordant deliveries were excluded. MZT rate was calculated as the number of multiple pregnancies (more than one gestational sac at first ultrasound) out of the total number of clinical pregnancies. A binomial distribution model was used to determine the 95% CI of the frequency of MZT.

RESULTS

Eighteen centers were included, and they provided data on 10,433 pregnancies. The total number of MZT was 162, corresponding to an incidence of 1.5% (95% CI: 1.3-1.8%). The rate of MZT among centers varied between 0% (95% CI: 0.0-25.9%) and 3.2% (95% CI: 1.3-8.1%). All the 95% CIs included 1.5%, rejecting the hypothesis that the MZT rate may significantly differ among centers.

CONCLUSIONS

The rate of MZT did not significantly vary among ART centers. Local factors are unlikely to explain the increased rate of MZT in ART pregnancies.

Oxidative Stress and Assisted Reproduction: A Comprehensive Review of Its Pathophysiological Role and Strategies for Optimizing Embryo Culture Environment

Oxidative stress (OS) due to an imbalance between reactive oxygen species (ROS) and antioxidants has been established as an important factor that can negatively affect the outcomes of assisted reproductive techniques (ARTs). Excess ROS exert their pathological effects through damage to cellular lipids, organelles, and DNA, alteration of enzymatic function, and apoptosis. ROS can be produced intracellularly, from immature sperm, oocytes, and embryos. Additionally, several external factors may induce high ROS production in the ART setup, including atmospheric oxygen, CO2 incubators, consumables, visible light, temperature, humidity, volatile organic compounds, and culture media additives. Pathological amounts of ROS can also be generated during the cryopreservation-thawing process of gametes or embryos. Generally, these factors can act at any stage during ART, from gamete preparation to embryo development, till the blastocyst stage. In this review, we discuss the in vitro conditions and environmental factors responsible for the induction of OS in an ART setting. In addition, we describe the effects of OS on gametes and embryos. Furthermore, we highlight strategies to ameliorate the impact of OS during the whole human embryo culture period, from gametes to blastocyst stage.

Taking a closer look at the key performance indicators in an assisted reproductive technology laboratory: a guide for reproductive professionals

Over the years, laboratories performing assisted reproductive technologies have been tasked with a growing number of procedures of increased complexity. New technologies, including hardware and software innovations, are constantly evolving, and being evaluated as potential tools to improve laboratory and clinical outcomes. The ART laboratory plays a crucial role in fertility treatments and, therefore, it is often under intense scrutiny with regards to performance and success rates. As the reproductive medicine field strives to deliver improved clinical outcomes to patients, IVF clinics - including the ART laboratories - are required to monitor their performance and seek improvement in the many different aspects related to patient care. Key Performance Indicators (KPIs) and benchmarking are important tools to support performance monitoring and quality improvement processes. The concept and potential benefits of KPI utilization is generally accepted. However, its adoption poses some challenges that may discourage ART practices from pursuing it as part of their Quality Management Systems (QMS). Properly selecting and using KPIs will allow laboratories to successfully manage their performance and set up realistic target goals to consistently deliver high rates. Existing literature can guide reproductive medicine professionals to embark on their journey to successfully select, implement, and manage KPI and benchmarking as part of their ART programs. This article discusses the concept and essentials of KPI and benchmarking applied to the ART laboratory, as well as potential challenges and how to overcome them.

An expert commentary on essential equipment, supplies and culture media in the ART laboratory

The ART laboratory is a complex system designed to sustain the fertilization, survival, and culture of the preimplantation embryo to the blastocyst stage. ART outcomes depend on numerous factors, among which are the equipment, supplies and culture media used. The number and type of incubators also may affect ART results. While large incubators may be more suitable for media equilibration, bench-top incubators may provide better embryo culture conditions in separate or smaller chambers and may be coupled with time-lapse systems that allow continuous embryo monitoring. Microscopes are essential for observation, assessment, and micromanipulation. Workstations provide a controlled environment for gamete and embryo handling and their quantity should be adjusted according to the number of ART cycles treated in order to provide a steady and efficient workflow. Continuous maintenance, quality control and monitoring of equipment is essential and quality control devices such as the thermometer, and pH-meter are necessary to maintain optimal culture conditions. Tracking, appropriate delivery and storage conditions, and quality control of all consumables is recommended so that the adequate quantity and quality is available for use. Embryo culture media have evolved: preimplantation embryos are cultured either by sequential media or single-step media that can be used for interrupted or uninterrupted culture. There is currently no sufficient evidence that any individual commercially-available culture system is better than others in terms of embryo viability. In this review, we aim to analyse the various parameters that should be taken into account when choosing the essential equipment, consumables and culture media systems that will create optimal culture conditions and provide the most effective patient treatment.

Effect of ambient air pollutants on in vitro fertilization-embryo transfer pregnancy outcome in Zhengzhou, China

With the acceleration of China's urbanization and industrialization, air pollution has become a major environmental problem. Retrospective data analysis of 6564 patients who underwent IVF-ET in the center for reproductive medicine of the First Affiliated Hospital of Zhengzhou University from 2015 to 2020. Different stages were selected from 90 days before oocyte retrieval to 35 days after transfer and divided into five exposure periods. Multivariate logistic regression was used to analyze the relationship between six ambient air pollutants (PM_2.5, PM₁₀, NO₂, SO₂, CO and O₃) and the IVF-ET pregnancy outcome. The results showed that air pollutants can significantly affect the IVF pregnancy outcome. The harmful effects of ambient air pollutants are more obvious in the patients aged < 35 years, single embryo transfer and cleavage stage embryo transfer.

Time-Lapse Systems: A Comprehensive Analysis on Effectiveness

Time-lapse systems have quickly become a common feature of in vitro fertilization laboratories all over the world. Since being introduced over a decade ago, the alleged benefits of time-lapse technology have continued to grow, from undisturbed culture conditions and round the clock, noninvasive observations to more recent computer-assisted selection of embryos through the development of algorithms. Despite the global uptake of time-lapse technology, its real impact on clinical outcomes is still controversial. This review aims to explore the different features offered by time-lapse technology, discussing incubation, algorithms, artificial intelligence and the regulation of nonessential treatment interventions, while assessing evidence on whether any benefit is offered over conventional technology.

Tripronuclear Zygotes in IVF Laboratory Quality Control: Experimental Evaluation and Potential Applications

This study set out to evaluate quality control within a new in vitro fertilization (IVF) laboratory environment and of new incubators based on the culture results of tripronuclear zygotes. The representative environmental indicators within new and old IVF laboratories were monitored, and tripronuclear zygotes were cultured in the two laboratories; the results were analyzed and compared. Subsequently, tripronuclear (3PN) zygotes were cultured in both new and old incubators and the culture results were compared. No differences were found in embryo development between 3PN zygotes in the old and new laboratories. However, in the quality control test, the degeneration rate and developmental arrest rate in the new incubator early phase group were significantly increased when compared with the old incubators. Moreover, the grade I embryo rate also decreased significantly. Nevertheless, all the above comparisons in the new incubator later phase group showed no statistical significance as compared to those observed in old incubators. Tripronuclear zygotes are sensitive to the environment in IVF laboratories and can be considered useful during quality control trials of new IVF laboratories and new equipment including incubators.

Common practices among consistently high-performing in vitro fertilization programs in the United States: 10-year update

OBJECTIVE

To evaluate similarities and differences in clinical and laboratory practices among high-performing fertility clinics.

DESIGN

Cross-sectional questionnaire study of selected programs.

SETTING

Academic and private fertility practices performing in vitro fertilization (IVF).

PATIENT(S)

Not applicable.

INTERVENTION(S)

A comprehensive survey was conducted of 13 IVF programs performing at least 100 cycles a year and having high cumulative singleton delivery rates for 2 years.

MAIN OUTCOME MEASURE(S)

Clinical and laboratory IVF practices.

RESULT(S)

Although many areas of clinical practice varied among top programs, some commonalities were observed. All programs used a combination of follicle-stimulating hormone and luteinizing hormone for IVF stimulation, intramuscular progesterone in frozen embryo transfer cycles, ultrasound-guided embryo transfers, and a required semen analysis before starting the IVF cycle. Common laboratory practices included vitrification of embryos at the blastocyst stage, air quality control with positive air pressure and high-efficiency particulate air filtration, use of incubator gas filters, working on heated microscope stages, and incubating embryos in a low-oxygen environment, most often in benchtop incubators.

CONCLUSION(S)

Some areas of consistency in clinical and laboratory practices were noted among high-performing IVF programs that are likely contributing to their success. High-performing programs focused on singleton deliveries. As the field of IVF is rapidly evolving, it is imperative that we share best practices in an effort to improve outcomes from all clinics for the good of our patients.

The in vitro fertilization laboratory: teamwork and teaming

Delivery of fertility treatment involves both teamwork within a discipline as well as teaming across multiple work areas, such as nursing, administrative, laboratory, and clinical. In contrast to small autonomous centers, the in vitro fertilization (IVF) laboratory team in large clinics must function both as a team with many members and a constellation of teams to deliver seamless, safe, and effective patient-centered care. Although this review primarily focuses on teamwork within the IVF laboratory, which comprises clinical laboratory scientists and embryologists who perform both diagnostic and therapeutic procedures, it also discusses the laboratory's wider role with other teams of the IVF clinic, and the role of teaming (the ad hoc creation of multidisciplinary teams) to function highly and address critical issues.

Associations between ambient air pollution and IVF outcomes in a heavily polluted city in China

RESEARCH QUESTION

Is air pollution related to IVF outcomes in a heavily polluted city in China?

DESIGN

A retrospective cohort study of 8628 fresh, autologous IVF cycles was conducted for the first time at the Reproductive Medicine Center of The Third Affiliated Hospital of Zhengzhou University between May 2014 and December 2018 (oocyte retrieval date). The exposure was divided into four periods (gonadotrophin injection to oocyte retrieval [P1], oocyte retrieval to embryo transfer [P2], 1 day after embryo transfer to embryo transfer +14 days [P3] and gonadotrophin injection to embryo transfer +14 days [P4]) and four levels (Q1-Q4 according to their 25th, 50th and 75th percentiles).

RESULTS

An interquartile range increase (Q2 versus Q1) in particulate matter ≤10 µm (PM10) during P3 and P4 and sulphur dioxide (SO₂) during P3 significantly decreased the clinical pregnancy rate (adjusted odds ratio [aOR] 0.81, 95% confidence interval [CI] 0.71-0.92 for PM10 of P3; aOR 0.87, 95% CI 0.76-1.00 for PM10 of P4; aOR 0.82, 95% CI 0.73-0.93 for SO₂ of P3). In addition, PM10 was associated with an increased biochemical pregnancy rate (Q3 versus Q1: aOR 1.55, 95% CI 1.09-2.19 for PM10 of P1) and decreased live birth rate (Q2 versus Q1: aOR 0.88, 95% CI 0.77-0.99 for PM10 of P3). The multivariate regression results were consistent with that of multiple treatments propensity score method (PSM) for SO₂ pollutants in P3 and PM10 pollutants in P4.

CONCLUSION

From the early follicular stage to the pregnancy test period, high concentrations of PM10 and SO₂ may have a negative impact on IVF treatment outcomes in the study area.

The Mare: A Pertinent Model for Human Assisted Reproductive Technologies?

Although there are large differences between horses and humans for reproductive anatomy, follicular dynamics, mono-ovulation, and embryo development kinetics until the blastocyst stage are similar. In contrast to humans, however, horses are seasonal animals and do not have a menstrual cycle. Moreover, horse implantation takes place 30 days later than in humans. In terms of artificial reproduction techniques (ART), oocytes are generally matured in vitro in horses because ovarian stimulation remains inefficient. This allows the collection of oocytes without hormonal treatments. In humans, in vivo matured oocytes are collected after ovarian stimulation. Subsequently, only intra-cytoplasmic sperm injection (ICSI) is performed in horses to produce embryos, whereas both in vitro fertilization and ICSI are applied in humans. Embryos are transferred only as blastocysts in horses. In contrast, four cells to blastocyst stage embryos are transferred in humans. Embryo and oocyte cryopreservation has been mastered in humans, but not completely in horses. Finally, both species share infertility concerns due to ageing and obesity. Thus, reciprocal knowledge could be gained through the comparative study of ART and infertility treatments both in woman and mare, even though the horse could not be used as a single model for human ART.

Off-gassing plasticware to decrease the toxicity effect in embryo culture

Objective:

Methods:

Results:

Conclusions:

Infection precautions for severe acute respiratory syndrome coronavirus 2 in assisted reproduction centers: dodging an invisible bullet

The coronavirus disease 2019 pandemic has resulted in many changes in how we interact in society, requiring that we protect ourselves and others from an invisible, airborne enemy called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Until a vaccine is developed, and it reaches high levels of distribution, everyone must continue to be diligent to limit the viral spread. The practice of assisted reproduction during this pandemic presents unique challenges in addition to the risks identified in general clinical care. The established good tissue practices employed in laboratories are not designed to protect gametes and embryos from an airborne virus, particularly one that may be shed by an asymptomatic staff member. Armed with theoretical risks but lacking direct evidence, assisted-reproduction teams must examine every aspect of their practice, identify areas at a risk of exposure to SARS-CoV-2, and develop a mitigation plan. Several professional fertility societies have created guidelines for the best practices in patient care during the coronavirus disease 2019 pandemic. As we learn more about SARS-CoV-2, updates have been issued to help adapt infection-control and -prevention protocols. This review discusses what is currently known about SARS-CoV-2 infection risks in assisted reproductive centers and recommends the implementation of specific mitigation strategies.

Air quality in the clinical embryology laboratory: a mini-review

The scope of the clinical embryology laboratory has expanded over recent years. It now includes conventional in vitro fertilization (IVF) techniques and complex and time-demanding procedures like blastocyst culture, processing of surgically retrieved sperm, and trophectoderm biopsy for preimplantation genetic testing. These procedures require a stable culture environment in which ambient air quality might play a critical role. The existing data indicate that both particulate matter and chemical pollution adversely affect IVF results, with low levels for better outcomes. As a result, IVF clinics have invested in air cleaning technologies with variable efficiency to remove particulates and volatile organic compounds. However, specific regulatory frameworks mandating air quality control are limited, as are evidence-based guidelines for the best air quality control practices in the embryology laboratory. In this review, we describe the principles and existing solutions for improving air quality and summarize the clinical evidence concerning air quality control in the embryology laboratory. In addition, we discuss the gaps in knowledge that could guide future research to improve clinical outcomes.

Cryopreservation and Thawing of Human Ovarian Cortex Tissue Slices

Cryopreserved ovarian cortex tissue can be used to improve or restore female fertility. It can be used for cancer patients to restore fertility after chemotherapy treatment or for social reasons for women who want to postpone their pregnancy wish. In order to preserve ovarian tissue viability in these cases, the tissue needs to be stored by cryopreservation. In this chapter we describe the entire process chain needed to prepare, transport, and cryopreserve human ovarian cortex tissues as well as to subsequently thaw and implant it.

COVID-19 risk assessment and safety management operational guidelines for IVF center reopening

PURPOSE

To promote nationwide dissemination and implementation of COVID-19 Risk Assessment and Safety Management Operational Guidelines, drawn up by SAMeR Task Force in ART centers in Argentina. Our objective is to prevent and mitigate the transmission of SARS-CoV-2 at an institutional level, while reducing the risk of infection among both physicians and patients in the context of a critical scenario in the local and Latin American healthcare system.

METHODS

SAMeR Executive Committee set up a crisis committee which was made up of specialists in reproductive medicine, embryology, and healthcare management. A critical and updated review of the advances in science, documents, and recommendations released by other societies (ASRM, ESHRE, IFFS, Red LARA, societies of anesthesiologists, infectious diseases, and Occupational Safety and Health Administration-OSHA) was carried out. Likewise, there were joint meetings with the Ministry of Health of Argentina in order to draw up the guidelines. Simultaneously, ongoing medical training was carried out, thus providing added value to them, including two status surveys of the activities of the monovalent and polyvalent centers according to the country's epidemiological mapping. Four additional recommendations were made, and online training was given to healthcare workers. The aforementioned regulations were first analyzed by the healthcare providers and their practical suggestions were then added to the guidelines.

RESULTS

The one-off collaborative work and the actions coordinated with the National ART Program of the Ministry of Health of Argentina resulted in the development and implementation of the present COVID-19 Risk Assessment and Safety Management Operational Guidelines at a national level. SAMeR gave recommendations for the implementation of the Management Guidelines for the center reopening, providing new safety criteria against the threat of viral contagion. A new organizational culture was promoted through the awareness of all the healthcare workers and teaching responsibility. We continue working on the compliance with a new "Code of Conduct and Commitment in Healthcare" and with workplace safety measures. We helped with transforming the theoretical knowledge into practical measures for the healthcare workers in different services, with the aim to prevent, mitigate, and/or handle contingencies at the centers/services and gamete banks, in line with the actions agreed upon with the Ministry of Health.

CONCLUSIONS

As an extraordinary and uncertain event, the SARS-CoV-2 pandemic helped consolidate a volunteer-based and collaborative panel of SAMeR experts who developed the COVID-19 Risk Assessment and Safety Management Operational Guidelines as a new and readily available tool for physicians, patients, and gamete banks care. Their implementation has provided specific guidelines to minimize risk for professionals in ART clinics, as well as guaranteeing patient safety.

Seasonal variation, temperature, day length, and IVF outcomes from fresh cycles

PURPOSE

It is known that delivery rates from spontaneous conception vary according to season which may be due to cultural or environmental factors; however, conflicting data exist regarding whether outcomes from IVF are also seasonally dependent. The present study was designed to test the hypothesis that the season at oocyte retrieval is associated with livebirth after fresh transfer.

METHODS

Dates of oocyte retrieval for all autologous cycles in our IVF program between January 2012 and December 2017 were categorized by season. Dates were linked to local temperature (min, max, average) and day length obtained from meteorological records. Average maximum temperature and day length were categorized into tertiles. Multivariable logistic regression, adjusted for age and quadratic age, were used to model odds (aOR) of implantation, clinical pregnancy, spontaneous abortion, and livebirth.

RESULTS

Patient characteristics were similar across seasons. As expected, temperature and day length varied by season. When compared with cycles started during winter, there was no difference in the age-adjusted odds of livebirth for the other three seasons (spring: aOR: 0.97, 95% CI: 0.82-1.13; summer: aOR: 1.05, 0.90-1.23; fall: aOR: 0.98, 0.84-1.15). There was a positive linear trend between temperature and odds of implantation, and clinical pregnancy (p value, test for linear trend (implantation, p = 0.02; clinical pregnancy, p = 0.01)) but no association with livebirth for temperature or day length.

CONCLUSIONS

We found that season at oocyte retrieval was not associated with livebirth, contrary to patterns seen in naturally conceived populations. However, our data did suggest modestly higher odds of clinical pregnancy for retrievals in June and July, and that higher temperature at time of retrieval was associated with higher odds of clinical pregnancy but not livebirth.

Association between outdoor air pollution during in vitro culture and the outcomes of frozen-thawed embryo transfer

STUDY QUESTION

Does outdoor air pollution differentially affect the outcomes of frozen-thawed embryo transfer (FET) and fresh transfer in IVF treatment?

SUMMARY ANSWER

Increased SO2 and O3 levels at the site of IVF unit were significantly associated with lower live birth rates following FET but did not affect the contemporary fresh transfer outcomes.

WHAT IS KNOWN ALREADY

Ambient air pollution has been associated with human infertility and IVF outcomes. However, most of the studies excluded FET cycles.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of 11148 patients contributing to 16290 transfer cycles between January 2013 and December 2016 was carried out.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The average age of the cohort was 31.51 ± 4.48 years and the average BMI was 21.14 ± 2.37 kg/cm2. Inverse distance weighting interpolation was used to estimate the daily ambient exposures to six pollutants (PM2.5, PM10, SO2, NO2, CO, O3) at an IVF clinical site, according to the data from fixed air quality monitoring stations in the city. The exposures of each cycle were presented as average daily concentrations of pollutants from oocyte retrieval to embryo transfer/cryopreservation. Exposures were analyzed in quartiles. A generalized estimating equation was used to evaluate the association between pollutants and IVF outcomes, adjusted for important confounding factors including maternal age, infertility diagnosis, BMI, endometrial status and embryo transfer policy.

MAIN RESULTS AND THE ROLE OF CHANCE

The clinical pregnancy rate and live birth rate of the cycles was 55.1% (8981/16290) and 47.1% (7672/16290), respectively. Among the included cycles, 4013 patients received 5299 FET cycles, resulting in 2263 live births (42.7% per ET), whereas 9553 patients received 10991 fresh transfer cycles, resulting in 5409 live births (49.2% per ET). SO2 and O3 levels were significantly associated with live birth rates in FET cycles, whereas none of the pollutants were significantly associated with IVF outcomes in contemporary fresh transfer cycles. The FET cycles in the highest quartile of SO2 and O3 exposure had significantly lower live birth rates (adjusted odds ratio (OR) 0.63, 95%CI 0.53-0.74; 0.69, 95% CI 0.58-0.82, respectively) in comparison with those in the lowest quartile. Models involving all transfer cycles and interaction terms (FET×exposures) suggested that FET significantly enhanced the effects of SO2 and O3 exposure on IVF outcomes (P < 0.001). Multi-pollutant models gave consistent results for the association between SO2 and live birth in FET cycles. Accounting for all six pollutants, women in the highest quartile of SO2 still had the lowest live birth rates (OR 0.61, 95%CI 0.47-0.80).

LIMITATIONS, REASONS FOR CAUTION

The study was limited by its retrospective nature. The exposure data were estimated according to monitoring data rather than measured directly from the IVF unit. Unknown confounding factors may skew the results.

WIDER IMPLICATIONS OF THE FINDINGS

Our data implied that embryos undergoing FET may be more vulnerable to a suboptimal environment than those undergoing fresh transfer. In heavily polluted sites or seasons, fluctuation in FET outcomes may be partially explained by the dynamic changes of ambient gaseous air pollutant.

STUDY FUNDING/COMPETING INTEREST(S)

National Natural Science Foundation (81302454). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Assessment and management of the risk of SARS-CoV-2 infection in an IVF laboratory

Research question

The study set out to identify corrective measures aimed at reducing the risk of aerosol-mediated viral infection within an IVF laboratory.

Design

A failure modes and effect analysis (FMEA) was conducted by a multidisciplinary IVF team. A schematic representation of new protocols and procedures adopted during COVID-19 emergency has been defined, including directives about the behaviour to adopt when entering the clinic and the laboratory, in case of face-to-face contact with patients and between staff members. In addition, the risk of cross-contamination between samples belonging to different patients during cell handling and manipulation has been evaluated. Potential failure modes for each phase of the emergency have been analysed, focusing on possible sources of error. Risk priority numbers have been calculated as products of Occurrence × Severity × Detection scores.

Results

Except for cell–cell contamination, which was considered highly unlikely, failure modes during patient–staff, staff–staff and staff–cell interactions were estimated as carrrying a moderate to high risk of infection. The main corrective measures entailed precautionary logistic measures, the implementation of additional personal protective equipment and changes in the IVF laboratory procedures and scheduling of the daily routine. Some procedures were also revised, aiming to increase staff's awareness and caution.

Conclusions

Standard laboratory protocols are insufficient to face a virus whose transmission is aerosol mediated. The measures outlined in this FMEA should thus be considered not only for facing this pandemic, but also for the future to promptly manage any aerosol-mediated virus infection, whose impact on the management of an IVF laboratory might be less severe than COVID-19 although not completely negligible.

Managing the IVF laboratory during a pandemic: international perspectives from laboratory managers

Fertility societies worldwide responded to the COVID-19 pandemic by recommending that fertility clinics close, or sharply reduce, the clinical operation, leading to a shift in the management of IVF laboratories in three phases: shutdown preparation; maintenance during shutdown; and restart. Each of these phases carries distinct risks that need identification and mitigation, forcing laboratory managers to rethink and adapt their procedures in response to the pandemic. The sudden and unprecedented nature of the pandemic forced laboratory managers from around the world to base decisions on opinion and experience when evidence-based response options were unavailable. These perspectives on pandemic response were presented during a virtual international symposium on COVID-19, held on 3 April 2020, and organized by the London Laboratory Managers’ Group. Laboratory managers from seven different countries at different stages of the pandemic (China, Italy, Spain, France, UK, Brazil and Australia) presented their personal experiences to a select audience of experienced laboratory managers from 19 different countries. The intention of this paper is to collect the learnings and considerations from this group of laboratory managers who collaborated to share personal experiences to contribute to the debate surrounding what constitutes good IVF laboratory practice in extraordinary circumstances, such as the COVID-19 pandemic.

Triple-arm trial of pH (Tri-pH) effect on live birth after ICSI in Egyptian IVF facilities: protocol of a randomised controlled trial

INTRODUCTION

One potential stressor that can affect preimplantation and postimplantation embryonic growth after in vitro fertilisation (IVF) is the pH of the human embryo culture medium, but no evidence exists to indicate which pH level is optimal for IVF. Based on anecdotal evidence or mouse models, culture media manufacturers recommend a pH range of 7.2 to 7.4, and IVF laboratories routinely use a pH range of 7.25 to 7.3. Given the lack of randomised trials evaluating the effect of pH on live birth rate after IVF, this trial examines the effect of three different pH levels on the live birth rate.

METHODS AND ANALYSIS

This multicentre randomised trial will involve centres specialised in IVF in Egypt. Eligible couples for intracytoplasmic sperm injection (ICSI) will be randomised for embryo culture at pH 7.2, 7.3 or 7.4. The study is designed to detect 10 percentage points difference in live birth rate between the best and worst performing media with 93% power at a 1% significance level. The primary outcome is the rate of live birth (delivery of one or more viable infants beyond the 20th week of gestation) after ICSI. Secondary clinical outcomes include biochemical pregnancy, clinical pregnancy, ongoing pregnancy, miscarriage, preterm births, birth weight, stillbirth, congenital malformation and cumulative live birth (within 1 year from randomisation). Embryo development outcomes include fertilisation, blastocyst formation and quality, and embryo cryopreservation and utilisation.

ETHICS AND DISSEMINATION

The study was reviewed and approved by the Ethics Review Boards of the participating centres. Eligible women will sign a written informed consent before enrolment. This study has an independent data monitoring and safety committee comprised international experts in trial design and in vitro culture. No plan exists to disseminate results to participants or health communities, except for the independent monitoring and safety committee of the trial.

TRIAL REGISTRATION NUMBER

NCT02896777.

Microbial contamination in assisted reproductive technology: source, prevalence, and cost

Even the strictest laboratories and clinics are prone to the occurrence of microbial contamination. In the case of in vitro fertilization (IVF) research and practice facilities, the number of possible sources is particularly vast. In addition to ambient air, personnel, and non-sterilized materials, follicular fluid and semen from patients are a very common gateway for a diverse range of bacteria and fungi into embryo cultures. Even so, reports of contamination cases are rare, what leads many clinics to see the issue as a negligible risk. Microbiological contamination may result in the demise of the patient's embryos, leading to additional costs to both the patient and the clinics. Regardless of financial loss, emotional costs, and stress levels during IVF are highly distressing. Other worrisome consequences include DNA fragmentation, poor-quality embryos, early pregnancy loss or preterm birth, and possible long-term damages that need further investigation. In this review, we aimed to shed a light on the issue that we consider largely underestimated and to be the underlying cause of poor IVF outcomes in many cases. We also discuss the composition of the microbiome and how its interaction with the reproductive tract of IVF-seeking patients might influence their outcomes. In conclusion, we urge clinics to more rigorously identify, register, and report contamination occurrences, and highlight the role of the study of the microbiome to improve overall results and safety of assisted reproduction.

Temperature of embryo culture for assisted reproduction

BACKGROUND

'Infertility' is defined as the failure to achieve pregnancy after 12 months or more of regular unprotected sexual intercourse. One in six couples experience a delay in becoming pregnant. In vitro fertilisation (IVF) is one of the assisted reproductive techniques used to enable couples to achieve a live birth. One of the processes involved in IVF is embryo culture in an incubator, where a stable environment is created and maintained. The incubators are set at approximately 37°C, which is based on the human core body temperature, although several studies have shown that this temperature may in fact be lower in the female reproductive tract and that this could be beneficial. In this review we have included randomised controlled trials which compared different temperatures of embryo culture.

OBJECTIVES

To assess different temperatures of embryo culture for human assisted reproduction, which may lead to higher live birth rates.

SEARCH METHODS

We searched the following databases and trial registers: the Cochrane Gynaecology and Fertility (CGF) Group Specialised Register of Controlled Trials, the Cochrane Central Register of Studies Online, MEDLINE, Embase, PsycINFO, CINAHL, clinicaltrials.gov, The World Health Organization International Trials Registry Platform search portal, DARE, Web of Knowledge, OpenGrey, LILACS database, PubMed and Google Scholar. Furthermore, we manually searched the references of relevant articles and contacted experts in the field to obtain additional data. We did not restrict the search by language or publication status. We performed the last search on 6 March 2019.

SELECTION CRITERIA

Two review authors independently screened the titles and abstracts of articles retrieved by the search. Full texts of potentially eligible randomised controlled trials (RCTs) were obtained and screened. We included all RCTs which compared different temperatures of embryo culture in IVF or intracytoplasmic sperm injection (ICSI), with a minimum difference in temperature between the two incubators of ≥ 0.5°C. The search process is shown in the PRISMA flow chart.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias and extracted data from the included studies; the third review author resolved any disagreements. We contacted trial authors to provide additional data. The primary review outcomes were live birth and miscarriage. Clinical pregnancy, ongoing pregnancy, multiple pregnancy and adverse events were secondary outcomes. All extracted data were dichotomous outcomes, and odds ratios (OR) were calculated with 95% confidence intervals (CIs) on an intention-to-treat basis. We assessed the overall quality of the evidence for the main comparisons using GRADE methods.

MAIN RESULTS

We included three RCTs, with a total of 563 women, that compared incubation of embryos at 37.0°C or 37.1°C with a lower incubator temperature (37.0°C versus 36.6°C, 37.1°C versus 36.0°C, 37.0° versus 36.5°C). Live birth, miscarriage, clinical pregnancy, ongoing pregnancy and multiple pregnancy were reported. After additional information from the authors, we confirmed one study as having no adverse events; the other two studies did not report adverse events. We did not perform a meta-analysis as there were not enough studies included per outcome. Live birth was not graded since there were no data of interest available. The evidence for the primary outcome, miscarriage, was of very low quality. The evidence for the secondary outcomes, clinical pregnancy, ongoing pregnancy and multiple pregnancy was also of very low quality. We downgraded the evidence because of high risk of bias (for performance bias) and imprecision due to limited included studies and wide CIs.Only one study reported the primary outcome, live birth (n = 52). They performed randomisation at the level of oocytes and not per woman, and used a paired design whereby two embryos, one from 36.0°C and one from 37.0°C, were transferred. The data from this study were not interpretable in a meaningful way and therefore not presented. Only one study reported miscarriage. We are uncertain whether incubation at a lower temperature decreases the miscarriage (odds ratio (OR) 0.90, 95% CI 0.52 to 1.55; 1 study, N = 412; very low-quality evidence).Of the two studies that reported clinical pregnancy, only one of them performed randomisation per woman. We are uncertain whether a lower temperature improves clinical pregnancy compared to 37°C for embryo incubation (OR 1.08, 95% CI 0.73 to 1.60; 1 study, N = 412; very low-quality evidence). For the outcome, ongoing pregnancy, we are uncertain if a lower temperature is better than 37°C (OR 1.10, 95% CI 0.75 to 1.62; 1 study, N = 412; very low quality-evidence). Multiple pregnancy was reported by two studies, one of which used a paired design, which made it impossible to report the data per temperature. We are uncertain if a temperature lower than 37°C reduces multiple pregnancy (OR 0.80, 95% CI 0.31 to 2.07; 1 study, N = 412; very low-quality evidence). There was insufficient evidence to make a conclusion regarding adverse events, as no studies reported data suitable for analysis.

AUTHORS' CONCLUSIONS

This review evaluated different temperatures for embryo culture during IVF. There is a lack of evidence for the majority of outcomes in this review. Based on very low-quality evidence, we are uncertain if incubating at a lower temperature than 37°C improves pregnancy outcomes. More RCTs are needed for comparing different temperatures of embryo culture which require reporting of clinical outcomes as live birth, miscarriage, clinical pregnancy and adverse events.

Practical Considerations in Providing Preimplantation Genetic Testing for Aneuploidies (PGT-A)

Preimplantation genetic testing for aneuploidies (PGT-A) has been controversial in its application to improve reproductive success, reduce time-to-pregnancy, and serve the intention-to-treat. Nevertheless, many in vitro fertilization (IVF) units have already introduced the service for one reason or another. Given PGT-A is not a stand-alone technique but a clinical service involving several disciplines, this mini review discussed the factors that can influence success rates when PGT-A is applied and highlighted practical issues encountered by clinicians, embryology, and genetics laboratories involved in the provision of PGT-A service.

[Impact of air quality on practices and results in the IVF laboratory]

The concept of Air Quality often refers to particulate and microbiological contamination of ambiant air. European Directive 2006/86/CE encompass the IVF process and specify a class A air quality for manipulation of tissue and cells, in a class D environment (A over D rule). Recognizing the paramount importance of ensuring the highest microbiological and particulate safety in the IVF laboratory, it is equally important to take into account practicability issues and the financial burden of these recommendations, as well as the utter need to protect gametes and embryo viability during their IVF journey. The usefulness of such stringent recommendations may also be questionned given the absence of published cases of airborne contaminations and related patients infections after embryo transfer. The European directive stems from pharmaceutical standards and were not specifically designed for human IVF. Gametes and embryos are indeed extremely sensitive to physical and chemical stress and require strict temperature, osmolarity and pH control, as well as an absence of chemical contamination during manipulation and culture. These conditions are hardly obtained when using laminar flow hoods. Following concerns raised by many experts in the field, exceptions to the A over D rule were added in the 2006/86/CE Directives. This narrative review discusses all these aspects in a critical way and compare scientific and legal requirements applying to IVF practices in different regions of the world.