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 started our IVF process with LWC around a year ago. It felt very daunting and a long road ahead, and the entire team were so supportive and explained everything so clearly. When we were undergoing the egg retreival and transfer, the team were so kind and we felt really looked after. We have now welcomed our little girl and after years of trying, we wouldn't have gotten here without the support and guidance given by LWC. Thank you all!’

Alice Maker

22 January 2026, LWC London Bridge

‘Dr Suraya made our appointment a really enjoyable experience. She made us both feel at ease and was so knowledgeable throughout the scan. Dr Suraya is a real asset to LWC’

Liz Troup

22 January 2026, LWC London Bridge

‘I received excellent care from all the staff at London Women's Clinic, we felt very welcomed as a same sex couple. We are so grateful to have been able to have our wonderful daughter. I would definitely recommend the clinic to anyone starting fertility treatment!’

Megan Knox

21 January 2026, LWC Canterbury

‘I've recently completed a round of egg freezing with London Women's Clinic harrow and I couldn't recommend them as a clinic more. Carla and Ana-Maria quite literally held my hand throughout the entire process, making me feel really relaxed and supported. It's made such a stressful experience super positive and if anyone is thinking of using them, I'd absolutely recommend them!’

Brooke Day

19 January 2026, LWC Harrow

‘I undertook Kind IVF, which even though is nurse led as opposed to consultant led, the care, professionalism and knowledge is there. The nurses consult with consultants during your protocol, so the difference really is you see the nurses instead. The medication doses are less and less medication, but this doesn't mean it will be less effective, it is an option worth exploring, as the cost is less and can open the door when more traditional ivf is out of reach. I am currently pregnant having gone through the kind ivf protocol one time.’

APINTOF MEGAN

19 January 2026, LWC London Bridge

‘Exceptional service from start to finish. Highly recommend Harley street team for looking after us. Absolutely loved your service and care. Thank you London woman's clinic :)’

Anh Nguyen

19 January 2026, LWC Harley Street

‘The team at the Cambridge LWC branch have been incredibly supportive, encouraging and helpful throughout our journey, and have been with us through the ups and downs. It's a very safe and inclusive space, and we feel very well cared for. We can't recommend them enough! Sarah and Jacqui’

Sarah Peace

16 January 2026, LWC Cambridge

‘We will be forever grateful to London Women's Clinic Bromley for helping us achieve what once felt impossible -- welcoming our beautiful, healthy baby boy in November 2025. Our IVF journey was emotional, overwhelming at times, and deeply personal, but from the very first appointment we were met with nothing but kindness, compassion, and unwavering support. Every step was clearly explained, we were kept fully informed throughout, and there was always someone available to answer our questions or simply reassure us when we needed it most. We never once felt like just another patient -- we felt truly cared for. Dr Malini, Sarah, Nicky (Nikita) and Dom were exceptional and will always hold a very special place in our hearts. Their warmth, patience, and genuine kindness made the process so much easier to cope with. They made us feel safe, comfortable, and supported during some of the most vulnerable moments of our lives. Every nurse, embryologist, and member of staff we encountered was wonderful. We honestly cannot recommend London Women's Clinic Bromley enough to anyone struggling with fertility or facing similar challenges. The dedication, empathy, and expertise of this team has changed our lives forever. We hope to take the clinic up on their offer to visit with our little miracle, who we are endlessly thankful they helped bring into this world. Thank you from the bottom of our hearts. Lucy & Sayed ’

Lucy morgan

16 January 2026, LWC Bromley

‘My journey with egg freezing in the LWC has been amazing. I had started consultations with another provider before but didn't feel comfortable there, and I'm SO GLAD I listened to my instinct and went to this clinic! The whole team was so knowledgeable and supportive throughout, but also just lovely. I would recommend the clinic, ESPECIALLY if you are worried about the process and feel emotional, the understanding and support here is way beyond what I was hoping for!!!’

Charlotte M

15 January 2026, LWC London Bridge

‘My journey with the LWC in London Bridge + Harley Street has been outstanding. The team is so lovely, I felt welcomed and understood from the first to the last call and through every appointment in between. I would recommend it to every friend!’

Charlotte M

15 January 2026, LWC Harley Street

‘Nicki has a beautiful and excellent personality, she was so kind, polite and sweet. I felt so happy after the scan . Bless her. Right woman for the job.’

Steave Oyinloye

15 January 2026, LWC Bromley

‘Nikita was fab - really put me at ease with my scan and able to relax. Feel very supported’

S S

15 January 2026, LWC Bromley

‘Just had my scan with Nikki and she was very informative and made me feel very comfortable.’

Lisa

15 January 2026, LWC Bromley

‘Nikita was excellent and mindful during our initial scan/consultation explained everything well.’

james harris

15 January 2026, LWC Bromley

‘Myself and partner have had a lovely experience with LWC Canterbury they are thoughtful and caring. Always made us feel comfort and welcome even through the difficulties that we have faced on our journey, however we will be forever grateful for all they have done and are contiuing to do.’

Natasha Elliott

14 January 2026, LWC Canterbury

‘This was my first fertility treatment, and I cannot express enough how thankful I am to have chosen LWC and to have been treated at the Harrow clinic. I would highly recommend it to anyone considering starting their fertility journey! From the start, I appreciated how transparent the admin team was about all the costs involved at every stage, giving clear ranges when the decision depended on how the treatment would go. I am also extremely grateful for their support in helping with securing financing, even when I decided to move forward at short notice. They took the time to schedule calls to answer my questions, and I truly felt listened to and cared for as a patient. At the Harrow clinic, I experienced an exceptionally caring and positive environment. All the nurses were highly professional while also being incredibly comforting and supportive. I would especially like to thank Ana Maria, who was there throughout the process, offering practical advice based on her own experience, a hug when needed, and making the entire journey feel much more like home. I would also like to thank Carla for her positivity, high energy, and encouragement during difficult moments, and Laura for her empowering and reassuring approach to the injections. Dr Goswami was also outstanding--extremely professional and clear in her advice. She carefully adjusted the treatment to aim for the best possible outcome while prioritising safety and minimising risks. I am also very grateful for the support groups organised by the clinic. Through these, I met incredibly brave and empowered women and couples. Sharing this journey with some of them made the experience far more bearable and positive. Thank you to everyone at the Harrow clinic and LWC for your incredible support!!’

Marina Riabiz

14 January 2026, LWC Harrow

‘We had a very positive experience at this IVF clinic and would highly recommend it. From the very beginning, we felt well supported and looked after throughout the entire journey. A special thank you to Safak, our patient coordinator, who was incredibly helpful and always very quick to respond. We would also like to thank Princess, the receptionist, as well as the Italian receptionist whose name we unfortunately don't remember, for always being kind and welcoming. We are extremely grateful to Dr Suraya, who performed many of our scans and was exceptional throughout the process, and to Dr Rao, who followed our journey step by step with great care, professionalism and attention. Finally, a big thank you to all the nurses, especially Hannah,Ella and Paige, for their support, kindness and professionalism. Overall, we felt very well cared for and supported, and we truly recommend this clinic to anyone considering IVF!’

Alicia Gioia

12 January 2026, LWC London Bridge

‘The reception staff are amazing nothing is to much trouble. Always answered any queries we had. The whole team were brilliant from our first initial appointment too our very last. They made us feel so comfortable.’

Rachel Powell

12 January 2026, LWC Bristol

‘We don't know where to begin, this place truly is wonderful. So so comforting and welcoming. Every single staff member went above and beyond and really felt like family. We couldn't be more appreciative of everyone who helped us on our way to creat our little one, who is cooking away nicely at 20 weeks. From choosing a sperm donor to my egg collection and then to getting my wife pregnant with the embryos a few months later, it was so stress free and we felt supported every single step of the way. We can't thank all the lovely wonderful ladies at the Brentwood clinic enough for what they have helped us achieve- and of course the amazing people at the Harley street clinic for doing the procedures who were just as welcoming! Thank you all so so much, we can't wait to bring our little man to meet you all when we are ready to try for baby number 2 xxxxx’

molly bannister

9 January 2026, LWC Brentwood

‘Following a seminar I attended at LWC, I arranged a consultation with Dr. Naware who specialises in fertility for women over 40. It was a refreshing experience. Dr. Naware is empathetic, kind and thorough. The follow up from the clinic was excellent, with Safak, Patient Coordinator, providing regular updates.’

A Patel

9 January 2026, LWC London Bridge

‘We are incredibly grateful to London Women's Clinic - Canterbury for their outstanding care and support throughout our IVF journey. Both the Canterbury and Bromley teams surrounded us with genuine kindness, understanding, and constant attention. We always felt listened to and truly cared for, and the level of professionalism was exceptional at every stage. Thanks to their dedication and hard work, we had the chance to welcome our beautiful little daughter into the world. We cannot recommend this clinic highly enough.’

Natalia Twardochleb

8 January 2026, LWC Canterbury

‘We can't recommend the London Women's Clinic enough. My partner and I are a same-sex female couple and are currently pregnant with our baby due in July -- after only two attempts. From the moment we chose the London Women's Clinic, the experience was incredible. The Harrow branch in particular felt so welcoming and supportive. Carla Lang, Ana-Maria, Laura Adagbon, and Dr Gill were absolutely amazing -- accommodating, kind, friendly, and genuinely caring. They went above and beyond throughout our entire journey, even responding to emails outside of working hours, which meant so much to us. We had previously completed blood tests and scans at another clinic but didn't feel it was the right fit. The London Women's Clinic didn't push us to repeat everything unnecessarily -- they accepted our previous tests, which really showed that they are not money-driven. On that note, their pricing is also very affordable compared to other clinics. Dr Gill is incredibly thorough and precise, taking so many factors into account when planning treatment, which gave us complete confidence. Our insemination was carried out at the Harley Street London Women's Clinic by Dr Yogita Date, who was equally wonderful. She made us feel comfortable, supported, and genuinely wished us luck during the procedure. Overall, this clinic felt more like family than a medical service. Even now, they continue to check in on us and our pregnancy, which says everything about the level of care they provide. We are beyond grateful and wouldn't hesitate to recommend the London Women's Clinic to anyone starting their fertility journey.’

Maisie Thomas

8 January 2026, LWC Harrow

‘The team at LWC Harley Street have been outstanding. They have supported my wife and I through our IVF journey at every step, keeping us informed and making the entire journey feel seamless. A special thanks to Dr Serra, Nurse Mimi, Vita and the rest of the LWC team that have helped us along the way. We are now 20 weeks into our pregnancy and LWC have continued to follow up to ensure all is well. A big thank you once again and we highly recommend LWC Harley Street to anyone considering IVF.’

Keyur Nakum

29 December 2025, LWC Harley Street

‘Cannot fault the ladies here at all. I felt so so welcome and looked after during the visit and consultation. The nurses were so compassionate and lovely, and I really felt like I was being listened to and understood. Would recommend to anyone looking to start a fertility journey/make some enquiries into their fertility healthxx’

Ellie Brown

19 December 2025, LWC Canterbury

‘Myself and my partners experience with LWC in Canterbury has been AMAZING! They have been so supportive and friendly throughout our whole IVF journey and gave us no stress throughout any part of it. Would very highly recommend as our first round of ISCI IVF worked ’

Mia Summers

19 December 2025, LWC Canterbury