Best Practices in Embryo Preservation: Efficiency, Traceability, and Technological Innovation in Assisted Reproduction4o

Embryo preservation through cryopreservation has become a fundamental pillar in modern assisted reproduction clinics. Today, virtually all in vitro fertilization (IVF) programs use vitrification of surplus embryos to preserve their viability and offer more opportunities for future pregnancy. In fact, ultra-rapid cooling vitrification is recommended as the standard of care for human embryo cryopreservation due to its proven effectiveness.

This innovative technique has surpassed the older slow-freezing method, achieving post-thaw embryo survival rates close to 100% and pregnancy rates equal to or even higher than those obtained with fresh embryos. In other words, a properly vitrified and preserved embryo can offer virtually the same success rate as a never-frozen embryo, which has revolutionized clinical strategies (for example, enabling “freeze-all” cycles or freezing while awaiting genetic testing results).

However, guaranteeing the safe preservation of vitrified embryos requires the adoption of standardized best practices and the support of technological innovation to maintain maximum biological quality, ensure traceability of each sample, and optimize laboratory processes. Below, we review globally recognized best practices in the management of cryopreserved embryos—from international guidelines to recent advances—and how the use of infertility software and next-generation assisted reproduction software is improving efficiency, traceability, and clinical outcomes in this field.

Best Practices in Embryo Cryopreservation

Fertility and embryology scientific societies (such as ASRM and ESHRE) have established clear guidelines to ensure that embryo cryopreservation is performed under optimal safety and quality conditions. Some of the most recognized international best practices include:

Standardized protocols and trained personnel: It is essential to have validated protocols for vitrification and warming, and to continuously train embryology staff in their correct application. A consistent and competent technique enhances efficiency, reliability, and procedural safety.

Laboratories should regularly conduct competence assessments and quality audits on the cryopreservation process.

Identification and double verification: Implementing double verification of patient and sample identity at all critical steps—such as loading embryos into cryo-straws for freezing and during warming—is essential to avoid sample mix-ups.

All critical steps must be documented in the patient’s record, including the date, time, and operator responsible.
This detailed record allows each embryo to be tracked throughout its journey in the lab.

Labeling and complete records: Each vial containing embryos must be clearly and permanently labeled with the patient’s unique identification.

Documentation of stored embryos should include information such as the freezing technique used, type and batch number of cryoprotectant, embryo developmental stage at the time of freezing, number of embryos per straw (ideally no more than two), and total number of straws stored per patient.

Likewise, every warming procedure must be recorded, noting details such as post-thaw embryo survival and its evolution before transfer.

Avoiding contamination and ensuring biosafety: To minimize cross-contamination risk from pathogens, it is recommended to use closed vitrification systems (sealed devices) that prevent direct contact between the embryo/media and liquid nitrogen.

Furthermore, samples from patients with known infectious diseases must be stored in separate tanks or clearly identified according to local regulations.

Patients must also be tested for viruses like HIV and hepatitis before cryopreservation, as required by European directives.

Cryogenic tank monitoring: Maintaining consistently low temperatures is a critical aspect of safe preservation. Every lab should have systems to monitor liquid nitrogen tanks, including alarms for low LN₂ levels and oxygen sensors to detect excessive evaporation in the room.

Tanks should be placed in dedicated and controlled areas, and backup tanks should be readily available. These measures help prevent accidents like unnoticed nitrogen depletion. Real-life incidents of tank failure—which led to the thawing of thousands of embryos in IVF centers—have been attributed to inadequate monitoring and lack of alarms/redundancies, highlighting the importance of this aspect.

Regular audits and inventory checks: Keeping an up-to-date inventory of all vitrified embryos is essential. Guidelines recommend conducting at least one annual audit of cryopreserved samples, cross-referencing database records with the physical content of each tank.

Additionally, records should reflect the exact location of each straw (e.g., tank number, canister, position) within the cryobank. Rigorous tracking makes it easier to locate a sample when needed and to quickly detect any discrepancies or missing straws.

In addition to these practices, clinics should implement a quality management system aligned with international standards. Holding certifications like ISO 9001, or specific standards such as UNE 179007 (developed in Spain for assisted reproduction laboratories), helps ensure that all these processes are formalized and consistently followed.

A strong quality system also ensures compliance with European regulations on cell traceability and safety, building trust among both professionals and patients.

Traceability and Safety: Absolute Control of Oocytes and Embryos

Traceability refers to the ability to identify, locate, and track every biological sample at all times. In an assisted reproduction laboratory, maintaining traceability of oocytes, sperm, and embryos is crucial to avoid identification errors, which can have serious consequences. Best practices indicate that each laboratory must have an effective and precise system to uniquely identify and track every embryo throughout each procedure.

Traditionally, traceability was ensured through manual double-checks by embryologists (manual witnessing). However, human involvement always carries the risk of oversight or distraction—especially in high-volume labs. For this reason, Electronic Witnessing Systems (EWS) have become widely adopted in recent years to support or replace manual verification. These systems use barcode or RFID (Radio Frequency Identification) technology to label all elements: tubes, dishes, straws, and containers are linked to the corresponding patient using scannable codes or RFID chips. Thus, at every stage—oocyte retrieval, fertilization, culture, vitrification, transfer, etc.—the system automatically verifies that the sample being handled matches the correct patient’s identity.

These computerized Witness systems offer continuous traceability throughout the entire IVF process, right up to the final storage location of the sample in the cryopreservation tank, using a sequence of electronic "matching" steps. Each event (e.g., moving an embryo from a dish to a straw) is digitally documented, creating a complete chain of custody. This not only ensures greater safety but also improves efficiency by eliminating the pauses required for manual double-checking.

A recent comparative study highlighted that using electronic witnessing reduced verification time by 3 to 5 times compared to traditional manual procedures, significantly streamlining lab workflow. Moreover, over 78% of surveyed embryologists felt that EWS improved sample traceability and reduced labeling errors, providing them with “peace of mind at the end of the day”, knowing that no step went unverified.

Security in vitrified embryo management goes hand in hand with traceability. It requires strict control over who handles each sample and when, ensuring that no sample is lost or misused. Every movement must be recorded; for example, if a vitrified embryo is transferred, donated, or discarded, the event must be logged both in the patient's record and in the embryo bank registry. Advanced clinics also apply Failure Mode and Effects Analysis (FMEA) to identify critical points where identification errors could occur and implement preventive measures accordingly.

In summary, robust traceability means being able to reconstruct the complete history of every embryo at any time—from the collection of the parental gametes to its current status—with total certainty.

Technological Innovation in Embryo Preservation

Technology is playing an increasingly important role in optimizing embryo preservation and minimizing associated risks. While other aspects of IVF (such as fertilization, culture, and even embryo selection) have advanced rapidly, the storage and handling of cryopreserved samples have remained relatively static for decades.

Even today, many labs still use Dewar-type liquid nitrogen tanks, invented in the 19th century, and manage frozen embryo inventories on spreadsheets—or even paper. This manual approach is prone to errors and makes it difficult to manage the growing volumes of vitrified embryos resulting from strategies like fertility preservation, freeze-all cycles, and increased use of genetic testing that requires freezing before transfer.

Fortunately, new technological innovations are emerging in the field of cryopreservation to take safety and efficiency to the next level. Some key trends and developments include:

Automation and Robotics in Cryostorage

The first automated cryogenic storage systems for embryos and gametes are already available. In 2022, the FDA approved a robotic platform that digitizes the traceability and monitoring of frozen embryos.

These solutions integrate robotic hardware and specialized software to handle cryo-straws within automated tanks, controlling the temperature and exact location of each sample without human intervention. Studies suggest that cryobank automation can prevent catastrophic errors that are possible in manual processes (such as mix-ups, losses, or accidental thaws), while keeping samples under continuously monitored and documented conditions.

A well-designed robotic system virtually eliminates the risk of misidentification or loss, while optimizing the use of space and resources. Commercial platforms like TMRW Life Sciences even offer a digital registry and auditable custody chain for each sample and have replaced dozens of traditional tanks with a single automated module featuring advanced monitoring capabilities.

The arrival of these “Cryobanks 4.0” represents a major leap in safety and traceability for the clinics that adopt them.

Digital Management Systems and Big Data

End-to-end digital management of embryo preservation enables better data usage and reduces administrative workload. A modern assisted reproduction software functions like an electronic lab management system (LIMS or “smart lab”) where every event—from oocyte retrieval, fertilization, and in vitro development, to vitrification and eventual transfer or disposal—is stored in a unified database.

This structure makes it easier to analyze key performance indicators and clinical outcomes. For example, maintaining a structured cryopreservation database allows the extraction of stats such as survival rates, utilization rates of frozen embryos, and success rates by protocol, which helps continuously refine the process.

With the rise of big data, some clinics are beginning to apply advanced analytics to these historical records to detect patterns or factors influencing clinical success. Centralizing this information also streamlines daily operations: the software can automatically generate unique labels, schedule alerts for consent renewals, track legal storage time limits, and even integrate with billing systems to manage maintenance fees for vitrified embryos.

Artificial Intelligence (AI) for Monitoring and Decision Support

AI is finding multiple applications in IVF laboratories, and cryopreservation is no exception. In embryo preservation, AI algorithms can assist in real-time monitoring of tank and equipment conditions, learning patterns to detect anomalies (e.g., abnormal nitrogen consumption that may signal a leak).

AI can also optimize nitrogen refill scheduling or redistribute samples across tanks to maintain balanced loads. Another use lies in predictive analytics: by cross-referencing embryo characteristics, protocols used, and clinical outcomes, AI can identify which practices or materials correlate with higher survival and pregnancy rates, offering valuable feedback to improve protocols.

In general, AI functions as a silent assistant, monitoring critical parameters and supporting decision-making based on large volumes of data—something that would be nearly impossible to manage manually. Although these applications are still in early stages in many labs, they represent a growing frontier that could significantly enhance the quality and consistency of embryo preservation.

Blockchain and Data Security

One of the most intriguing developments is the experimental application of blockchain technology in embryo traceability. Since blockchain creates immutable and verifiable records of every transaction, some researchers have tested its use to document every step of the vitrification and warming process in a tamper-proof manner.

During the COVID-19 pandemic, a laboratory implemented blockchain for the first time to record the use of UVC-sterilized liquid nitrogen in a virus-free vitrification program for oocytes and embryos, ensuring inviolable traceability for every nitrogen batch and device used.

Although still an emerging technology in this field, blockchain has strong potential to ensure data integrity, adding an extra layer of trust (for example, allowing regulators or patients to verify that no records have been altered). In the future, management systems may incorporate blockchain to give patients and regulators absolute confidence in the history of each vitrified embryo.

All these innovations—along with advances in vitrification devices, IoT temperature sensors, and the previously mentioned electronic witnessing systems—represent what some authors call the rise of “deep tech” in cryobiology: the use of advanced technological tools (digitalization, automation, robotics, large-scale data analysis) to achieve maximum efficiency, efficacy, and consistency in the cryopreservation of gametes and embryos.

As a result, clinics can manage increasing volumes of vitrified embryos without compromising safety—and patients benefit from more reliable and transparent care.

Efficient Management of Vitrified Embryos and Clinical Outcomes

Strictly applying the described best practices and technologies leads to tangible improvements in both laboratory operational efficiency and clinical outcomes for patients:

Increased Efficiency and Productivity:
Automating routine steps (e.g., documentation, identification, monitoring) frees up time for the team to focus on higher-value tasks, such as assessing embryo quality. For example, using an electronic witnessing system saves valuable minutes in each procedure, reducing interruptions and accelerating workflow.

Overall, a well-equipped lab with infertility software and integrated digital systems minimizes repetitive manual tasks (like data transcription or paperwork checks), which reduces human error and enhances overall efficiency. This enables clinics to handle a larger number of cycles and samples with the same resources—an essential factor given the global increase in demand for fertility treatments.

Flawless Traceability and Regulatory Compliance:
When each embryo is electronically tracked from the start, the possibility of patient identification errors is virtually eliminated. This provides peace of mind to both clinics and patients, strengthening trust in the process. Likewise, automated documentation helps meet legal requirements for reporting and data storage (in some countries, for example, clinics are required to report on the status of stored embryos periodically).

In the event of audits or inspections, having a complete log for each sample—and having strictly followed validated protocols—protects the institution and ensures that all quality assurance measures have been met. Full traceability also enables rapid response to any incident, allowing clinics to take immediate corrective action and contain potential issues.

Improved Clinical Outcomes:
Ultimately, the goal of embryo preservation is to achieve successful pregnancies in the future. The combination of vitrification with high standards and technological control maximizes the probability of success. Longitudinal studies show that when cryopreservation is carried out using optimized techniques and strict quality control, post-warming embryo survival rates are exceptionally high, preserving the embryo’s implantation potential.

This translates into high clinical pregnancy and birth rates following the transfer of vitrified embryos—often comparable to, or even exceeding, those of fresh embryos.

Moreover, by avoiding errors or adverse events (such as contamination, accidental thawing, or incorrect embryo transfers), results are better protected: each embryo retains its opportunity to be successfully used when the time comes.

Enhanced traceability and continuous monitoring also help reduce stress for both staff and patients, who can trust that their embryos are in good hands. All of this leads to a virtuous cycle: a safe, efficient laboratory generates better outcomes, improving clinic success rates and patient satisfaction.

Smart Automation with REPROCopilot: Elevating Cryopreservation Excellence

In today’s world, leveraging advanced technological tools is no longer optional—it’s a core part of best practice. REPROCopilot is a clear example of how innovation can be applied to automate and optimize embryo preservation workflows in assisted reproduction clinics.

This comprehensive platform, specifically designed for fertility centers, includes an AI-powered cryopreservation and traceability solution that takes vitrified embryo management to the next level.

With REPROCopilot, professionals benefit from an all-in-one infertility and assisted reproduction software that seamlessly connects the lab, patient database, and cryobank. Its cryopreservation module continuously monitors frozen samples in real time, automatically logging every embryo entry and exit from tanks using smart readers and AI algorithms that verify identity matching.

This ensures that each vitrified embryo is correctly labeled, located, and linked to its clinical record without manual effort. Additionally, thanks to artificial intelligence, the system can anticipate needs—such as alerting when tank maintenance is required or suggesting the reorganization of samples based on their age or clinical priority—proactively optimizing cryobank operations.

Traceability is guaranteed 100%: from the moment an embryo is vitrified and entered into the database, REPROCopilot creates a permanent, auditable record of every movement. Embryologists can access detailed information about any straw (contents, freeze date, exact location, etc.) in seconds, significantly accelerating decision-making when planning a transfer or updating consents with the couple.

Furthermore, the platform helps standardize best practices by guiding users through digital checklists and protocols at each step, ensuring no critical control is missed.

In terms of efficiency, REPROCopilot reduces administrative workload: it generates automatic reports, tracks usage and success statistics for frozen embryos, and integrates with other areas (medical consultations, nursing, etc.), keeping all relevant information centralized. This not only saves time but also reduces transcription errors and ensures a more agile and accurate workflow across the clinic.

In conclusion, REPROCopilot embodies how technology can support fertility clinics and reproductive health professionals in managing vitrified embryos with excellence. By adopting an intelligent cryopreservation and traceability platform, assisted reproduction clinics can focus on what truly matters—providing the best care to their patients—while trusting that the technical and quality control aspects of embryo preservation are optimized.

Integrating solutions like REPROCopilot is a step forward into the future of assisted reproduction: a future where technological innovation and best practices work hand in hand to improve laboratory efficiency, sample security, and—ultimately—clinical outcomes.

The recommendations and data mentioned are based on practice guidelines and recent studies, including ESHRE/ASRM guidelines on IVF laboratories, as well as articles on traceability systems and safe cryopreservation.​ rbmojournal.com, i-ceat.com, pmc.ncbi.nlm.nih.gov, as well as news and technological innovations in the management of vitrified embryos​, tmrwlifesciences.com, pmc.ncbi.nlm.nih.gov, among others. These references support the importance of combining best practices with advanced tools to optimize embryo preservation for the benefit of clinics and their patients.