How embryos develop – from egg retrieval to blastocyst

After retrieval, the egg and sperm are combined, and if fertilisation is successful, your embryo spends the first few days growing in the lab under the expert care of our team. This blog will help guide you through these early embryo development steps before transfer or freezing.

Factors affecting embryo development

Embryo development is a complex process that requires a combination of genetic, environmental and physiological factors to progress successfully. To achieve good embryo development, we require:

Healthy egg and sperm

The egg and sperm provide the genetic blueprint for development. Each embryo needs a complete set of 46 chromosomes – 23 from the egg and 23 from the sperm. Some embryos inherit incorrect genetic instructions that can impact embryo development and make it harder for them to divide and grow as expected.

Mitochondrial energy

Embryos need energy to divide and grow, which is provided by mitochondria (tiny energy-producing structures in cells). Poor mitochondrial function can slow or stop embryo development.
Efficient metabolic function:

An embryo’s metabolic function provides both energy and the building blocks needed for development. This includes the creation of protein and fats, and the removal of waste products that can be toxic to the embryo. Together, these provide what the embryo needs for growth, cell division and viability.

Timely cell division

Embryos should ideally divide at a regular pace (2-cell, 4-cell, 8-cell, etc.). Uneven and/or delayed division can mean the embryo is of suboptimal quality and may not develop as expected.

Embryonic genome activation

Around Day 3 (see diagram below), embryos start using their own DNA instead of relying on maternal DNA (genetic code from the egg). If this DNA transfer is inadequate, interrupted or missing, this can slow or stop the development of an embryo.

Stable conditions

Embryos need the right temperature, oxygen and pH balance to grow. These factors are carefully assessed and monitored continuously in the laboratory environment.

Difficulties or inaccuracies in any of these processes can affect the way an embryo grows and can impact whether an embryo will reach the blastocyst stage (where it has divided into many cells), making it suitable for transfer or freezing.

Safeguarding your embryos is our highest priority

We understand how important every embryo is to your journey. That’s why we use the most advanced technology and scientifically proven methods to create the ideal environment for embryo development. From carefully performing every procedure to closely monitoring each embryo’s progress, our highly trained embryologists work tirelessly to give each embryo the best possible chance to grow and thrive.

We maintain strict laboratory conditions, including precise temperature, humidity and air quality control to mimic the natural environment as closely as possible. Our team carefully observes each embryo’s development at every stage. Even though not all embryos will reach the blastocyst stage, please know that we do everything in our power to maximise their potential. Your dream of building a family is at the heart of everything we do, and we are committed to providing the best possible care every step of the way.

If you have any questions about embryo development or your fertility journey, please reach out to Newlife IVF. In the meantime, let’s walk through the different stages of embryo development to help you better understand the process

Witnessing systems at Newlife IVF

What is IVF witnessing?

Witnessing in IVF refers to the process of confirming that the correct eggs, sperm and embryos are used for the correct patient at the correct time. It mitigates the risk of mismatched or misidentified samples.  At Newlife IVF, we take this responsibility extremely seriously, which is why we use both electronic and manual methods for accuracy and traceability.

RI Witness – electronic tracking for your peace of mind

Newlife IVF employs the RI Witness electronic witnessing system, which uses Radio Frequency Identification (RFID) technology to track and verify all eggs, sperm and embryos in the laboratory. Each patient is assigned an RFID card and every patient vessel (e.g. tubes, dishes and cryo-vessels) is labelled with a matching RFID tag, all of which are programmed with each patient’s unique IVF code and three points of identification.

How RI Witness works at Newlife IVF:

  • Patient RFID card: you are assigned an RFID card that is linked to your profile. This is used for identification during key procedures, such as egg retrieval and embryo transfer
  • RFID tags on all labware: all test tubes, dishes and cryo-vessels used to hold your biological material are labelled with RFID tags matched to your unique code and profile
  • Real-time monitoring: all lab workstations have RI Witness receivers that detect these tags automatically. The system logs and monitors every sample movement during the procedure in real-time
  • Mismatch protection: if a mismatch ever occurs – for example, if two different tags are brought into an area at the same time – RI Witness triggers an audible and visual alarm, and the procedure is stopped immediately to investigate and correct the issue. To further reduce the risk of mismatches, our embryologists strictly work with the biological materials of only one patient at a time at each workstation.

Cryostorage tracking

All biological material placed into cryostorage is barcoded and tagged using the RI Witness system.

Each cryo-vessel is labelled with:

  • Your full name
  • Date of birth
  • Unique IVF code
  • Date of freezing
  • Barcode is specific to the eggs, sperm or embryos stored inside.

These cold-resistant tags ensure identification is maintained even at ultra-low temperatures. When the material is removed from cryostorage, the barcode is scanned and cross-verified with RFID data and RI Witness, and double-witnessed by embryologists to confirm all points of identification.

Embryologist double-witnessing

In addition to RI Witness, every procedure is manually witnessed by two embryologists. This human double-checking system complements electronic witnessing and adds a layer of human judgement, visual verification and accountability.

Manual witnessing includes:

  • Verifying three patient identifiers (full name, DOB and patient unique IVF code)
  • Cross-referencing all vessel labels, barcodes and RI Witness tags
  • Confirming the procedure that is to take place
  • Checking the freeze dates and, for embryos, specific embryo numbers
  • Confirming the correct sample before and after thawing.

This step is essential when biological material is entering or exiting the laboratory, and before every procedure such as insemination, embryo transfer, embryo biopsy or cryopreservation.

Cryostorage safety – cryo-vessel monitoring and audits

Biological materials such as eggs, sperm and embryos are stored in specially designed devices (cryo-vessels) that are specific for very cold temperatures.  The cryo-vessel is tagged with a special tag that withstands very cold temperatures. The cyro-vessel includes the patient’s name, date of birth, unique IVF code and the date of the freezing, along with a unique barcode that is specific to that patient’s egg, sperm or embryo held within the individual device.

Every sample is:

  • Uniquely identified and traceable
  • Matched at any time using the RI Witness system and barcode
  • Manually verified when moved or thawed.

Regular audits are conducted, comparing all stored material against patient records, to ensure that what is in storage precisely matches what is documented in each individual file and the RI Witness log.

Thawing of stored biological material

When biological material is removed from cryostorage, the barcode is scanned and linked to the patient’s vessel via an RFID tag.  Removal of eggs, sperm or embryos from cryostorage is also witnessed manually by the embryologist performing the procedure and a second embryologist.  Before thawing the biological material, the embryologists will witness the three points of patient identification on the cryotag, the freeze date and, in the case of embryos, the specific embryo number on the cryotag. This is cross-referenced with the vessel the biological material will go into after thawing, and the RI witness system. A mismatch at any point will sound an alarm.

Only once all of these steps have been completed will the thawing of the eggs, sperm or embryos proceed.

Summary of witnessing measures at Newlife IVF:

  • Only one patient’s material is handled at each workstation at any time
  • All vessels and labware are RFID tagged and barcoded
  • The RI Witness system and the embryologist manual double-witnessing are used to confirm all details at every procedure
  • Cryostored material is linked to the patient via a barcode and the RI Witness system.
  • Regular audits verify that frozen material in storage matches patient records and the RI witness system.

Please ask us!

We understand IVF can be a time filled with both hope and uncertainty. Our systems are designed to mitigate risk and ensure your biological material is being managed with the highest levels of care, security and accountability. If you have any questions, please speak to a member of our team. We’re always happy to help you feel supported and informed.

Putting patients first – the secret to exceptional results

Today, that vision, combined with the collective expertise and experience of our fertility specialists and support staff, has earned Newlife IVF recognition as one of Victoria’s top-performing IVF clinics.

According to the latest figures reported by the Herald Sun (sourced from the Federal Government’s Your IVF Success website), Newlife IVF holds the highest IVF success rate in Victoria for women under 35, with an impressive 62.5% of embryo transfers resulting in live birth.

For women aged 35 to 42, Newlife IVF also leads with the highest birth rates per embryo transfer in Metropolitan Melbourne (31.7%), placing us third overall in Victoria for this age group.

‘We are delighted to share that we have had another great year for our patients, with our pregnancy and birth success rates consistently above the national average. Our fertility specialist team focuses on providing the best possible milieu for eggs to mature and embryos to implant, and our amazing embryologists focus on every aspect of the egg, sperm and embryo care to provide a nurturing environment to achieve their developmental potential,’ said Dr Nicole Hope, fertility specialist and Medical Director at Newlife IVF.

A vision for exceptional fertility care

As a clinician-owned and led fertility clinic, we’re proud to be one of the few independent specialist fertility centres in Victoria. This independence allows us to offer a more personalised, supportive experience than corporate-owned clinics.

‘We feel so privileged to play a part in our patients’ journeys. Being able to provide a level of care that helps them achieve their dream of starting a family is truly an honour for us,’ said Dr Tiki Osianlis, Newlife IVF’s Managing Director and Scientific Director.

Every aspect of our practice is designed with our patients’ needs in mind. From our state-of-the-art laboratory to our use of advanced scientific tools and techniques, we combine expert-led care with cutting-edge science to give our patients the best possible chance of building the family they dream of.

‘Our IVF success rates highlight how effective our approach is. It’s not just about the science – it’s about the people. The entire team, from our fertility specialists and nurses to our embryologists, counsellors and admin staff, take the time to truly understand each patient’s unique journey. We adapt our care to fit their needs, and every single one of us is genuinely invested in helping our patients achieve their dream of becoming parents,’ said Dr Tiki.

Giving you Newlife in a different way

At Newlife IVF, we believe that everyone deserves the opportunity to build their family, which is why we’re committed to making high-quality fertility treatment as accessible as possible. We remain committed to delivering outstanding results and compassionate care, empowering our patients with the best possible chance of success.

If you’re ready to explore your options for having a baby, you can make an appointment with one of our specialists by calling (03) 8080 8933 or by booking online.