28 July 2019

Is freezing embryos the future of IVF?

According to the latest HFEA figures, Frozen Embryo Transfer (FET) cycles have increased by 11%. We sat down with Andrew Thomson, the Laboratory Manager at LWC Wales to discuss this new trend.

According to the latest HFEA Trends and Figures report published in May 2019, Frozen Embryo Transfer (FET) cycles have increased by 11% between 2016 and 2017 whilst the number of fresh embryo transfers has dropped by 2%. For the first time, Frozen Embryo Transfer cycles are now more successful than fresh (23 vs 22%) based on the HFEA’s national figures.

Why have Frozen Embryo Transfer cycles seen such an increase?

During an IVF cycle we stimulate the patient’s ovaries before an egg collection procedure takes place. The collected eggs are then fertilised in the laboratory using IVF or ICSI to create embryos. The embryos are then cultured in the laboratory for around 5 days and closely monitored by a team of highly-skilled embryologists. Traditionally, we then replaced the best embryo (or sometimes two) back to the patient on day 5 and freeze any remaining good quality embryos.

Using the latest vitrification technology, embryos don’t deteriorate once frozen they are preserved at the age you are at the time of freeze. For example, if you were aged 35 when you froze the embryos, if you use them 5 years later, the embryos will still be 35! This means that today embryos can be thawed out and replaced in a Frozen Embryo Transfer (FET) cycle, when the patient is ready, with the same or better chance of success than in a fresh cycle.

Over the last few years, the scientific community have found that embryo transfer in a frozen cycle may produce better results. Due to the stimulation medication a patient is given prior to egg collection and the trauma of the egg collection procedure itself, an embryo transfer during this same cycle may not be the best or safest time. It could also reduce the chance of pregnancy. More clinics are opting to freeze the embryos and replace them in an FET cycle a month later or when the patient is ready.

An FET cycle uses minimal or no medication so one embryo can be replaced into a much more natural environment resulting in potentially higher success rate and hopefully a safer pregnancy. There has been a lot of research on this topic but at present there is still no consensus as to the best policy with different clinics favouring fresh or frozen embryos.

Has LWC Wales seen an increase in Frozen Embryo Transfer cycles?

Most definitely. The fasted growing trend in IVF is egg freezing but for us FET cycles have increased faster than any other treatment. In Cardiff, FET cycles increased by 32% (2017 vs 2018) and we’ve already done 20% more in 2019 compared to the same time in 2018!

How successful is a Frozen Embryo Transfer?

According to the latest HFEA national figures, FET is now more successful than a fresh embryo transfer. The latest success rates from the LWC Cardiff laboratory show that we have achieved great success with our FET programme over the last 15 months. When you compare the latest HFEA verified data in our region, our Cardiff laboratory comes top!

This success has been due to the Precision Embryology we have incorporated into the laboratory. We now have two time-lapse incubators and over 98% of our patients’ embryos are cultured using this technology (fresh and frozen). Pictures are taken of the embryos every 5 minutes without disturbing their environment, so we can easily track their development. We can then freeze or transfer the embryo at exactly the right time.

Based on the precision embryology principals, the Cardiff laboratory have achieved very high standards. On average 70% of the embryos we create make a blastocyst (a day 5 embryo required for freezing). If a patient has 4 or more fertilised eggs, more than 50% of the time the patient will have an embryo to transfer AND embryos suitable for freezing. This means patients treated at LWC Wales will achieve a high cumulative pregnancy rate by using their fresh and frozen embryos from one egg collection.

Patients should be aware that there is a very small chance the embryos will not survive the freezing and thaw process. In these instances, either another embryo will be thawed (if available) or the embryo transfer will be cancelled. At LWC Wales the survival rate of our frozen embryos after thawing is over 97% which is excellent!

What is precision embryo transfer?

The latest time-lapse technology in the laboratory helps our team of highly-skilled embryologists to decide the best time for embryo transfer. Viewing embryo development allows the embryologist to confirm whether to transfer on day 5 or to freeze the embryo for transfer in a later frozen embryo transfer cycle. This means that embryo transfer will be individually tailored to the patient to maximise success to you specifically.

This philosophy is different from standard embryology practice where embryos would be routinely replaced regardless of their development. Patients will also benefit from having a personal consultation with their designated embryologist to review the images of each of their embryos and to pinpoint exactly when the transfer will take place.

Are all embryos suitable for freezing?

At LWC Wales we only freeze blastocyst embryos that have fully expanded. For most embryos this will be on day 5 of development however sometimes this won’t happen until day 6 as some embryos are slower developmentally than others. Slow embryos are not suitable for freezing on day 5 and some clinics don’t even offer day 6 freezing meaning these embryos will be discarded. We have found from our data that there is no difference in success between an embryo that is frozen on day 5 or day 6 which is very interesting.

A recent study on slow blastocyst development suggests that day 6 embryos should be frozen and transferred in a later FET cycle rather than transferred fresh. Their study showed improved success rates for these patients and our own data supports this. The findings of our own study will be published later this year.

Is Frozen Embryo Transfer the future?

Quite possibly. Research into fresh vs frozen embryos will continue and LWC will be at the cutting edge of it. We presented our research this year at the Fertility Conference in Birmingham and we are currently working in conjunction with Cardiff University and another research group. We want to ensure the quality of our programme and that patients receive the best possible outcomes.

All of our blog posts are written, edited, or produced by the London Women's Clinic Content Team. This is a collaboration between our expert writers, health editors, and the leading researchers and senior doctors at our Harley Street clinic.

‘We have two beautiful children - our family wouldn't exist without LWC Brentwood. Can't recommend them highly enough; IVF is an emotional rollercoaster regardless of your journey and we were supported at every step. Pricing is transparent and easy to understand, with payment plans available that made accessing any treatment and medication very flexible and affordable. The clinic became such a part of our lives for that short time, the care and support is so important and LWC Brentwood were brilliant. Maybe we will see them again for number 3!’

Victoria Hayman

10 November 2026, LWC Brentwood

‘I would like to express my heartfelt thanks to the entire team for supporting me throughout my IVF journey. I am delighted to share that I had a positive pregnancy test following my very first IVF cycle fresh embryo transfer, and I am now 9 weeks pregnant! The staff at the LWC Colchester satellite clinic are very supportive, approachable and always do their best to help you at every stage of the journey. I would definitely recommend LWC Colchester to anyone considering fertility treatment. A special thank you to Dr Timea Kovats, a highly experienced, knowledgeable and to the wonderful staff Jackie, Annette, Tracey. Their excellent guidance, expertise, care and supportive approach played a significant role in making my first IVF cycle successful. I am truly grateful for their dedication, encouragement and support throughout this journey. I am equally grateful to all the staff at Colchester satellite clinic and the London main clinic for their care and support throughout the entire process. Thank you once again for helping us achieve such a special milestone in our lives. We will always be grateful for your support! ❤️’

jigu

10 November 2026, LWC Colchester

‘Friendly, experienced and professional team. Supported throughout the entire process and would highly recommend.’

Mizzee West

10 November 2026, LWC Brighton

‘The nursing team are so friendly and so supportive. Made everything so much better and easier to go through egg freezing.’

Megan Godber

10 November 2026, LWC Brighton

‘We had a great experience as the team here are very knowledgeable and caring and they made us feel taken care of throughout! Big shout out to Rute & Trianni for their care and support 😊’

Chiamaka Nelson

9 November 2026, LWC Cambridge

‘The team here are very kind and helpful and made the journey completely painless! They kept us informed throughout the process and were always responsive when we had questioned’

Aruna Nelson

9 November 2026, LWC Cambridge

‘They've given us wonderful service very easy to be around. Very good communication, and very good at helping us out with everything they've done so far.’

Jessica Norman

9 November 2026, LWC Oxford

‘We had a fantastic experience with LWC, Dr Rimington’s passion and expertise were second to none and we strongly believe that he is the reason for our success. All the staff were lovely, helpful and kind - we will definitely use LWC again’

Hannah Hale

9 November 2026, LWC Brighton

‘I honestly cannot recommend this fertility clinic highly enough. From the very beginning, the care, compassion and support we received were absolutely exceptional. Going through fertility treatment is an incredibly emotional journey, with so many ups and downs, but the team made us feel supported, listened to and genuinely cared for every step of the way. Nothing ever felt like too much trouble, and every member of staff we encountered was kind, understanding, professional and reassuring. What really stood out was how personal the experience felt. We never felt like just another number. The team took the time to answer our questions, put our minds at ease and guide us through what can sometimes feel like an overwhelming process. We are incredibly grateful for everything they have done for us and will never forget the part they have played in helping us grow our family. We now have our little miracles, and we couldn't be more thankful. If you're considering fertility treatment, I would wholeheartedly recommend LWC. Thank you from the bottom of our hearts for helping make our dream come true! ❤️’

Emma Hayman

8 November 2026, LWC Brentwood

‘Had a really positive experience visiting the Oxford Clinic. Nurse Manager Liv, took time to make me us feel at ease and explained how the appointment will go. Thank you!’

Kinga Arcana-Jones

7 November 2026, LWC Oxford

‘Everyone my partner and I have interacted with at the Oxford clinic has been warm, friendly and knowledgeable. They’ve really helped make a very daunting process easier to go through and I’m very glad we chose this clinic!’

Jess Palmer

5 November 2026, LWC Oxford

‘Very friendly staff and a lovely inclusive environment, had a wonderful experience here. Highly recommend for anyone looking at fertility preservation.’

T Ilagan

5 November 2026, LWC Oxford

‘As an LGBTQ couple we found LWC Colchester incredibly supportive, no question was too much. They were friendly and welcoming, with modern facilities, and made your journey feel very personalised. We would highly recommend them for your fertility journey.’

Jasmine Colman

5 November 2026, LWC Colchester

‘A massive thank you to Dom and Dr Vasquez for all of their help throughout the process!’

James Purcell

5 November 2026, LWC Tunbridge Wells

‘Me and my husband can’t thank everyone at London Women’s Clinic enough for all the care and support throughout our recent treatment. Everything went really well, and we are so grateful to all the doctors and the entire team for looking after me. A special thank you to Mimi, Dr Barbara, Caroline, Trina and Elena from Embryology team and the Theatre Team - Rose, Martin and Amy F. Everyone was so kind, helpful and reassuring, and it really made a difference. Thank you all for everything. ♥️♥️♥️♥️♥️’

IsadelandCyril

4 November 2026, LWC Harley Street

‘I would like to express my heartfelt gratitude and appreciation to the entire team who supported us throughout our IVF treatment. ❤️ A special thank you to Ana-Maria,our nurse, for her kindness, patience, compassion and professionalism. She was always so caring, understanding and supportive, making us feel reassured and comfortable during such an emotional and challenging journey. We would also like to thank Dr Gill from the bottom of our hearts for his professionalism, dedication, expertise and the confidence he gave us throughout the entire process. IVF is not just a medical treatment; it is an emotional journey filled with hope, challenges and many feelings. Having such wonderful people by our side made everything so much easier. Thank you for your care, support and dedication. We truly appreciate everything you have done for us and would wholeheartedly recommend you to anyone beginning their IVF journey. Thank you for being part of our journey! ❤️’

Alexandru Predescu

3 November 2026, LWC Harrow

‘I would like to express my heartfelt gratitude and appreciation to the entire team who supported us throughout our IVF treatment. ❤️ A special thank you to Ana-Maria,our nurse, for her kindness, patience, compassion and professionalism. She was always so caring, understanding and supportive, making us feel reassured and comfortable during such an emotional and challenging journey. We would also like to thank Dr Gill from the bottom of our hearts for his professionalism, dedication, expertise and the confidence he gave us throughout the entire process. IVF is not just a medical treatment; it is an emotional journey filled with hope, challenges and many feelings. Having such wonderful people by our side made everything so much easier. Thank you for your care, support and dedication. We truly appreciate everything you have done for us and would wholeheartedly recommend you to anyone beginning their IVF journey. Thank you for being part of our journey! ❤️’

Mihaela-Clemansa Predescu

3 November 2026, LWC Harrow

‘Simply Brilliant .’

Ramachandran Jeyamohan

3 November 2026, LWC Colchester

‘I feel so blessed and grateful to have been under the lovely nurse Katie and Dr Kovats’s care. Everyone I encountered in the clinic on or off line was friendly, reassuring, thoughtful, and patient with me. I could feel the genuine care from Katie and Dr Kovats. I feel very reassured knowing they'd be there with me every step of the way; it is a great relief to have medical professionals like them on my side. They listened attentively, were reassuring, explained what I need to know thoroughly and were very approachable. Thank you to Carina, the friendly clinic coordinator, for always answering my emails promptly and being so helpful with all the questions I threw at her. Also, to the lovely staff member with blonde hair (I’m so sorry I forgot your name!) who did the ultrasound scan, thank you for being so attentive and making me feel relaxed. The clinic has a calm, relaxing vibe and is very clean. I have had a wonderful experience with the clinic and would highly recommend the team to anyone on their fertility journey!’

T Yang

3 November 2026, LWC Brentwood

‘We have used London Women's Clinic twice in the last two years for successful egg retrieval and two subsequent frozen embryo transfers. We have always been met with care, compassion and a personal approach. Every step from the initial consultation right through to the 7 week scan has been professional and polite, always accommodating our needs and timings. We can't thank the team enough for giving us such support towards creating our family.’

Lucy Richards

2 November 2026, LWC Tunbridge Wells

‘Myself and my husband owe it all to london womens clinic, they were amazing from start to finish. We previously were under another clinic and decided to make the change due to many reasons and we are so glad we did. They treat everyone as individuals, not everyones fertility journeys are the same. The small team at Colchester make it so personable not to mention how amazing all 4 women are that work here, their knowledge empathy and listening skills simply cannot be found at any other clinic. The list goes on as to why I would recommend LWC but everyone likes a to the point review. They genuinely care they dont treat you like a number and they help you through every hurdle that occurs. Our little boy wouldn't be possible without these 4, each of them play a bigger part than they realise. 💙’

Ellen Turrell

2 November 2026, LWC Colchester

‘Wonderful punch of people, caring, competent, and efficient in all they do. It feels we are all in a mission together and they are invested in the success of our pregnancy. Thank k you 🙏’

Yasmine Mora

30 October 2026, LWC London Bridge

‘I couldn’t speak more highly of the London Women’s Clinic Oxford! From the moment you walk in you are greeted with such a warm welcome. The reception area is bright and welcoming and the receptionist is lovely. All of the staff are so friendly, helpful and polite. Going through this journey can be emotional, so having such a wonderful supportive, caring clinic to visit makes all the difference. Everyone goes above and beyond to make you feel comfortable and looked after. I feel so lucky to have such a lovely team supporting me along the way. Thank you all! 🍀💗’

Louise

30 October 2026, LWC Oxford

‘Incredible service and professionals. They made me feel comfortable and safe the entire journey. Thank you!’

Luciana Lombardi

30 October 2026, LWC Cambridge

‘I had an absolutely amazing experience at LWC from start to finish! There are literally no wait times so we were able to get started pretty much straight away after consultation. The process was seamless, with a lot of flexibility if you need to change appt time. Nurses are amazing and so supportive. Special shout out to Kate and Chris who were so kind and made the whole experience so much better. Also the nurses on the ward were absolutely amazing but I can’t remember their names. I’m now discharged as I’m pregnant from my first try! However I will look forward to returning in the future for my second embryo which is currently frozen 😊’

Kathryn Jessica

27 October 2026, LWC Bromley