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 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

‘We we under the care of Canterbury LWC for all scans and blood tests and Bromley for egg collection and transfers. The team and Canterbury were particularly amazing, so supportive and reassuring throughout. No question was ever too much, they treated you as individuals and were caring and compassionate throughout the process. The receptionist were lovely, knew you from the offset by name, remembered you which makes a difficult process so much easier when you are treated as an individual. We were NHS funded and I never felt we were treated any different to private patients. The nursing staff at Bromley were also brilliant, I always felt so looked after through some really tough and emotional procedures. We were under the care of Dr Uppal who was excellent, explained everything clearly, gave us options and listened to our concerns. Would highly recommend. Currently 26 weeks pregnant ☺️’

Rose S

25 October 2026, LWC Canterbury

‘We are incredibly grateful to London Women’s Clinic, Harrow, for helping make our dream of becoming parents come true. We are now blessed with a beautiful baby! A special thank you to Dr Gill for the care, guidance and support throughout our IVF journey, and to Carla and Maria for making the entire process smooth and reassuring. We had a wonderful experience and will always be thankful to the whole team. Highly recommend! ❤️’

P S

23 October 2026, LWC Harrow

‘LWC are fantastically supportive at every stage of your journey. They try to be as flexible as possible with appointments, giving good advice about supporting yourself (and partners) as you prepare for different procedures. It is a tough journey but Louise, Rute, Dr Arthi, Trianni, Dr Bishista and Ashley are incredibly supportive. Highly recommend them to anyone considering or needing fertility support.’

S W

23 October 2026, LWC Cambridge

‘I honestly cannot fault Kind IVF. From start to finish, I have been so incredibly impressed with the care, compassion and professionalism shown by the entire team. Going through IVF can be such an emotional and overwhelming journey, but they have made the whole experience feel so much more reassuring and positive. Every step of the way, I have felt cared for, listened to and supported. The team have been amazing at answering questions, putting my mind at ease and making sure I felt comfortable throughout the process. You can really tell how much they care about their patients, and that makes such a huge difference during a journey that can be so personal and emotional. I am so grateful to everyone at Kind IVF for everything they have done for us. Choosing them has been one of the best decisions we have made, and I genuinely couldn’t recommend them enough to anyone considering IVF. The standard of care has been outstanding, and I cannot thank them enough for helping us on this journey. ❤️ Thank you, Kind IVF, for being so amazing!’

Georgia Burt

22 October 2026, LWC Tunbridge Wells

‘I highly recommend the London Women's Clinic Brentwood. The staff were very supportive, patient, and always available to answer questions. They guided me through an emotional process with clear explanations and genuine care. The staff were always available and happy to help.’

S Begum

21 October 2026, LWC Brentwood

‘Choosing an IVF clinic is such a big decision and I'm so incredibly glad that we chose this one. IVF can be such an emotional and overwhelming journey but having a clinic that offers so much support and genuinely cares for you makes such a difference. The care and kindness that we have received has been exceptional. We can't thank LWC Brentwood enough ❤️’

Laura Keary

21 October 2026, LWC Brentwood

‘I honestly can’t thank London Women’s Clinic enough for helping me achieve my lifelong dream of becoming a mum. It wasn’t an easy journey, but the team were absolutely fantastic and supported me every step of the way. Their kindness, care and reassurance made such a difference during what was a really emotional and challenging time. I always felt supported and in safe hands. A special thank you to Carla, Ana-Maria and Dr Goswami. You have all been absolutely fantastic and I am so grateful for everything you have done for me. I’ll never forget the support and care you have shown me during such an important and emotional journey. Thank you all from the bottom of my heart for helping me achieve something I have wanted for as long as I can remember. It means more to me than words can say. I would recommend London Women’s Clinic to anyone going through their own fertility journey.’

Sarah

21 October 2026, LWC Harrow

‘We started our treatment in July, and I have had a very positive experience with this clinic. Lorraine on reception especially made me feel like nothing was too much trouble and always knew me by name which is such a nice personal touch, especially at such a sensitive time. Along with Dr Safwat Ashour he always recommended the best treatment for us and just had such a kind caring attitude towards us while explaining our options and being very honest with us too. One of the nurses (so sorry I can’t remember your name) she only recently started in July and I felt so at home with her and cared for. To finish off we are currently pregnant with our IVF miracle all thanks you this clinic. Thank you all so much, no thanks would ever be enough for the gift you have given us!’

Sophie Jay

21 October 2026, LWC Darlington

‘Very professional and very welcoming, and very clean I was given time to feel relaxed and I didn't feel like I had to rush this made me feel very comfortable.’

Ryan Harmer

21 October 2026, LWC Brighton

‘My wife and I have had a brilliant experience with LWC throughout our fertility journey. We always felt listened to, supported, and in control of the decisions we were making. Our PCC Suzanna, Dr Verstraete, and the nursing team were consistently friendly, responsive, and knowledgeable, which made navigating the shared motherhood process feel so much easier. We’re incredibly grateful for the care and support we received.’

Megan Nelkon

20 October 2026, LWC Harley Street

‘I’ve had a great experience with the clinic so far. From the very beginning, I’ve felt incredibly well cared for and supported throughout my egg freezing journey. Daenira on reception is always so lovely, welcoming and helpful, and Liv, my nurse, has been fantastic! She’s made me feel comfortable, reassured and well looked after at every step. Dr Wade has also been absolutely brilliant and I have complete confidence in the care and guidance I’ve received. I would highly recommend this clinic to anybody considering egg freezing.’

Saffy

20 October 2026, LWC Oxford

‘The most amazing experience with the clinic from start to end Nothing is to much for them They will answer every Question Worry or concern no matter how big or small, My experience and care they have shown in one of the hardest times and most worrying experiences they were there every single step of the way, I honestly couldn’t thank every member I’ve dealt with anymore and would recommend this clinic to anyone thinking about it , hardest decision but best decision every made and all the staff here made this possible for me you are all amazing caring people And I thank you from the bottom of my heart 🙏🏼🩷’

Stephanie

18 October 2026, LWC Brentwood

‘I truly feel blessed and thankful to God that we are in such a wonderful place and in such caring hands during one of the most precious journeys of our lives. The clinic has been outstanding throughout my treatment, making the entire journey feel as smooth as possible. The whole team at the Brentwood clinic is absolutely amazing, everyone is so warm, welcoming and supportive. The treatment has been incredible so far, and we are extremely satisfied with the care, support, and overall service we have received throughout our journey. Fingers crossed, I truly believe that the best news is just around the corner! ❤️🤞 I would wholeheartedly recommend Brentwood clinic for the care and support they provide in parenthood journey.’

Harika

14 October 2026, LWC Brentwood

‘London Women’s Clinic, Reading were fantastic and Nurse Nicky was such a supportive and reassuring professional. Thank you for journeying with me Nicky!’

Sope Adekola

14 October 2026, LWC Reading

‘Where to start… Fertility treatment is the last thing any of us expect to need. But if you find yourself on this journey, Brentwood London Women’s Clinic is where you want to be. Carina’s warm welcome sets the tone the moment you arrive, and every single nurse is wonderful, kind, calm, and reassuring. It’s a complicated and sometimes difficult road, but they walk it beside you. We’ve experienced both joy and heartache here, and through every moment we’ve felt cared for and supported. They truly get to know you, and the care feels personal and bespoke. Today we have our precious 3-year-old, and we will forever be thankful to this amazing team. They are everything you could hope for kind, knowledgeable, and genuinely there for you. We couldn’t recommend them more.’

Sarah Tidey

13 October 2026, LWC Brentwood

‘We honestly can’t thank London Women’s Clinic in Brentwood enough for everything they have done and continue to do for us. They helped us create our now 3 year old, and we are incredibly grateful to be back with them on our journey to hopefully have another little one. Angela and Katie are truly incredible nurses. They go above and beyond to make you feel comfortable, listened to and supported every step of the way. They take the time to explain the process, answer any questions and put your mind at ease, making what can sometimes be an overwhelming and emotional journey feel that little bit easier. It means so much to be cared for by people who genuinely seem to care about you and your family, rather than just seeing you as another patient. Their kindness, compassion and reassurance make such a difference, and we feel very lucky to have them supporting us again. We will always be grateful to London Women’s Clinic for helping us bring our little girl into the world, and we have every hope that they will help us grow our family once more. We couldn’t recommend the team highly enough. Thank you, Angela, Katie and everyone at the Brentwood clinic, for being such a special part of our journey. ❤️ Also a special mention for the smiley face in the reception. Carina, you are great!!’

bethan philp

13 October 2026, LWC Brentwood

‘Came here after my treatment at LWC Darlington as I needed to be part of the failed implantation team. The care and communication was second to none. It was everything and more, no question to my coordinator was never too much. They were extremely accommodating when I had to travel from up north multiple times and were always happy to let me have my then 2 year old son come to monitoring appointments. I’m grateful for their expertise in failed implantation as my 3rd egg collection was successful and my fresh transfer worked first time & I’ve just gave birth to my second LWC baby in September 2026. Would always recommend LWC - especially London Bridge / Harley Street.’

Jeni J

13 October 2026, LWC London Bridge

‘Great experience. Very kind and supportive.’

Jesylin Luka

12 October 2026, LWC Reading

‘My experience with London Women's Clinic Brighton has been wonderful so far. The staff are kind and patient, as well as exceptionally knowledgeable. I have had all my questions answered (and have been encouraged to ask more whenever!), and I feel assured that I'm receiving transparent, evidence-based advice.’

Jess Smith

12 October 2026, LWC Brighton