Blastocysts: 10 things IVF patients should know
Blastocysts have an image problem – and not just because they sound like a bad day at NASA. Should IVF patients transfer one or more? Is it a good idea to culture embryos for five days, not three? Are multiple births more or less likely? Here’s our round-up of the top 10 things you need to know about blastocysts – based on the most trusted research.
1. What is a blastocyst?
A blastocyst is a human embryo that’s five or six days old. Ten years ago, day-three embryos were routinely transferred in IVF cycles. Most clinics now believe that transferring better-developed embryos – i.e. those that have reached the blastocyst stage – makes an ongoing pregnancy more likely.
2. What does a blastocyst look like?
Under the microscope, a blastocyst is very different to a day-three embryo. There’s a fluid-filled cavity in the middle called the blastocoel. Another area, housing a dense collection of cells, is called the inner cell mass and will become the fetus. A third assortment of cells, near the central cavity, will form the placenta.
3. Is blastocyst transfer preferable to a day-three transfer?
The consensus is that an embryo that survives for five days is more viable for implantation and an ongoing successful pregnancy. Of course, many embryos don’t make it to day five. Where there’s a serious sperm-quality issue, for example, embryos will often stop developing by day three.
We also know that a better diet can help embryos get to day five – and numerous other studies point to the benefits of blastocyst formation and culturing. Blastocyst transfers can lead to better outcomes than earlier transfers.
4. Any other advantages in transferring blastocysts?
Blastocysts, on a purely biological level, can make things more straightforward for implantation. In natural conception, an egg will travel down a fallopian tube and be fertilised – hopefully. It may also connect to your endometrium at the right time – if you’re lucky. Placing a blastocyst directly into the womb, optimally timed, in a medicated cycle, between day 19 and 21, is an easier prospect for the hormonally-primed uterus.
5. Why don’t all IVF patients use blastocysts?
You may not get to day five. Depending on factors like your medical history, age, treatment choice, egg and sperm quality, your clinic may feel it’s safer to transfer a younger embryo. Or it may be the only option. Better to put in a tiddly one than none at all.
It’s also worth noting that good-quality blastocysts are more likely in donor-egg and donor-embryo cycles. Looking back at the donor patients we’ve helped, day-five blastocyst transfers have taken place on almost every occasion. IVF cycles can lead to earlier transfers, since gamete quality is less guaranteed. More can go wrong. But even then, day-five transfers in own-egg cycles happen a lot.
6. So do blastocysts lead to more IVF pregnancies?
Generally, yes. If you’re under 35, established research says that live birth rates after blastocyst transfer are higher than after cleavage-stage (earlier) transfers. Clinic data in the UK and across Europe shows that blastocyst transfers significantly boost clinical-pregnancy and live-birth rates. Typically we see pregnancy rates around 20 percentage points higher after day-five transfers. This applies across all age groups and all treatments. Cultivating a good number of top-quality blastocysts has also been shown to be a good predictor of future success.
7. Are there any drawbacks with blastocyst transfers?
Some patients worry that they’ll have fewer or no surplus embryos to freeze. This is a false argument. It’s better for get to day five and know your embryo quality. Yes, some embryos will be left behind. But you need to know that. With any luck, you’ll transfer the best one and have one or two good ones to freeze.
Freezing of embryos for a second attempt is often overlooked by IVF patients. The fact is that frozen embryo transfers, particularly those using blastocysts, are almost as successful as fresh ones. So here’s a tactic. If you have, say, two blastocysts on day five, freezing one and transferring the other may be sensible. In our case, each time we transferred two blastocysts, only one implanted. But we were in our 40s, an age range where implantation rates are a bit lower. Read about our success story here.
8. Do I transfer one blastocyst or two?
It’s firmly established that single embryo transfer is the way to go. Advances in extended cultivation technology and cryopreservation mean better quality embryos at the blastocysts stage and after freezing. The days of multiple embryo transfers are over, due to the well-known risks associated with multiple pregnancies. Read our blog post on this.
9. Twins after a single blastocyst transfer… what’s going on?
Blastocysts can split more easily than younger embryos, especially good-quality ones. So even a single blastocyst transfer can lead to twins (though it’s not common). The most dramatic scenario is if, after a double transfer, both blastocysts split and progress to live birth. Quadruplets, anyone? (This is very rare.)
10. So are blastocysts a good thing or not?
Yes, blastocyst transfer is the best option for most couples. In the distant past, some clinics would transfer up to four day-three embryos and hoped for the best. Blastocysts allow for more informed choices and better control over outcomes. While a 2019 study suggested blastocyst transfers increased the risk of premature birth and heavier babies, that risk was small. The routine approach to day-five transfers will continue.
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Anonymous
I am 27 years .have undergone endometrioma and myomectomy operation which spiked down my egg reserve from 5 to 1.8..I had egg retrieval which only 7 eggs were retrieved ,5 fertilized,had only 3 embryos on day 2,about to get a call from the embriologist on day 3..wishing and praying all survives and makes it to blastocyst stage..please pray for me
Dava
I got 2 embroys transferred 15 days back , one got implanted and other was not, What will happen to the failed embryo.?
Kay
I had 6 eggs collected and 5 fertilised 4 made day 5 blastosist. I had 1 transferred fresh cycle and 3 frozen my fresh embryo was negative and I’m now day 2 of fet 2 embryos put back in this is our last go now so nerves are shattered just really hope this time works and at least 1 implants can everyone cross your fingers for us please.
Kayte
Hoping if all works out for you
Alex
Did you get pregnant?
Mandm
Hi
I am in my 3 IVF try now . I har only 1 embryo fertilized and transfer. And to Say is my day 8 after dag 5 embry transfer. And the test was negative. Has anyone had any experience to share… please .? I am a latter lost!
Selvi
Hi.. im ttc for 8yrs. Im nearly 38yrs.. my last IUI failed. 1st time trying ivf. Last 27/11 retrieved 3eggs and only 1 egg fertilize. 30/11 will do embryo transfer.. im so worried .. will my ivf success with 1embryo transfer .. anyone hav experience it??
Mai Nat
Hello ladies.. i am 33 years, had 2 ectopic pregnancies in 2011 and 2016 and lost both my tubes. We started our IVf journey in January 2019 had 41 eggs retrieved, 19 fertilised (7 via ICSI & 12 on their own). They all were day 5+ embryos. i had to stop the cycle due to OHSS. It took 2 months for me to recover. I’m due for my first FET next Tuesday but the Dr. said he might not put back 2 embryos as they say i’m very fertile so they fear my embryos might split. I just pray the one survives and i get to carry my baby. I have been waiting for too long and in my country (Zimbabwe) you are shunned by family if you are married and dont have a child. Please pray for me, i am emotionally and financially drained
Mai Nat
Oh because of funds we only managed to freeze 8 embryos.
Hollifer
I will keep you in my prayers!
Deepika
Hi Mai Nat.. My story is same as yours.. My embryo transfer will happen in some where in january.. Tell me what happened after your transfer..
4DD
Hello,
I have a frozen 4DD blastocyst. (The lab uses the Gardner grading system.) It was frozen as it had developed further from an early blastocyst to 4DD from day 5 to day 6. Is it worth trying to use it? It seems it is not worth spending more money on this as the chances are so remote. What do you think? Do you freeze 4DDs?
Thank you.
Woods
Hi everyone. I have had 2 day 5 blastocyst embryo’s transfered and await a pregnancy test a week today. One embryo was a grade 4CD and the other an EB1 – so both very poor quality. I wish the clinic didn’t give me the grading as I have felt like they had no chance of surviving from the start. Had anyone had a positive from low grade embryos?
Lauren
Any luck with these embryos Woods?
Happy
We are both 30 (very low sperm count) long story short. 12 eggs retrieved, 9 suitable for icsi, 7 sucessfully fertilized, all 7 became day 5 blastocysts, of which 4 were good enough for transfer/freezing. We had 1 transferred and 3 frozen……. it split and now 13 weeks pregnant with twins!!!! So happy:-)
Lia
Im happy for you
Lia
I also had transferred one day 5 blastocyst.. now Im still waiting for beta hcg result.. im in day 4 after embrio transfer… Wish me luck like you do… And hope become twins also.. GBU
Sylvia Sajna
So happy for you
Christina
Congratulations!!!! I’m very excited for you. Did you find out at your 6 week ultrasound that you were pregnant with twins? What was your HCG level? I just had my single frozen embryo transfer and I’m praying that they split. My HCG is only at 174 at 12 days after transfer. I’m praying that it is still possible.
Shelley
I had one embryo transferred 6 days ago and have a strong bfp which is amazing compared to previous bfps, wondering if it’s split!
Marie
Hi, this is my first IVF cycle i am 39, I had an etopic a few years back in my last tube which was removed a few months ago to prepare for IVF..I had egg collection yesterday, they retrieved 22 eggs..I was advised yesterday to do a frozen cycle instead of a fresh one to prepare my womb..I received a call today 7 have fertilized so I will be doing blastocyst at day 5 to be frozen if of course they survive I am aware I may not get any after day 5.. I am receiving 2 embryo transfer if all goes well, pls pray for me!
Kerry
Hi Marie, hope all is going well.
I am a surrogate and I’m currently 7 weeks pregnant. We selected to have 1 5 day blastocyst transfer and just hoped for the best as we only had 3 viable eggs. It worked first time and as I said I’m now currently 7 weeks pregnant with identical twins.
I’m wishing you all the luck in the world with your fatility journey
Tasneem
I’m a 25 year old and Unsure if I must transfer 1 or 2 blastocysts.. did anyone experience a high risk pregnancy with transferring 2?
Elle
I transferred 2 blastocyst when I was 26 yrs. I had a singleton, normal pregnancy and my beautiful DD is almost 6yrs old and healthy!
Lorraine
Hi, I just want to give hope to all you wonderful people who see this page. In 2016 at age 44, I had 2 fresh cycle blastocysts transferred. At 6 weeks of pregnancy one foetus died (I thought all was lost in the bleed), but I was put on double progesterone for a few days till the blood loss stopped and a scan revealed our healthy day. She is now 19 months of age and perfection itself! I have this month returned to my clinic had my last 2 frozen embryos transferred (we had 4 in our original cycle. Both were great quality 1AA and 2BB and survived the thaw. I am now on day 5 post transfer and we wait patiently (and nervously) for our result. I am well apart from some small pink discharge so doc advised to leave off the aspirin for a few days and fingers crossed we can have success again. This is our last attempt as I am now 46 years old. To all who are on this journey, best of luck and have faith… I hope my story gives hope and we pray for the blessing of success again (even though I still cry for my lost twin) xx
DeNiece
Thank your for sharing! I’m 42 and just had egg retrieval two days ago. They only retrieved 4 eggs, and so far 3 out of the 4 have fertilized. Your story gives me hope!
Natalie
Hello did you get a BFP?
MEGHAN
HI LORRAINE,
HOPE YOU ARE PREGNANT AND DOING WELL. I’M 35 AND HAVE TWO MISCARRIAGES THIS YEAR. WE TRANSFERRED ON SEPERATE OCCASIONS TWO PGS NORMAL EMBRYOS AT 7.5 WEEKS MISCARRIED DUE TO SUBCHORIONIC HEMATOMA. I HAVE A SON FROM A FRESH CYCLE. WONDERING IF MY EMBRYOS DO BETTER FRESH.
GOOD LUCK WITH EVERYTHING. YOU GIVE ME HOPE.
MEGHAN
Judie
Thanks for sharing. I am inspired and encouraged by your story and wish you the best in your journey. xxxxx
Susan
Hi Lorraine
Your story is so inspiring. I am 44 yo and just had 10 eggs retrieved. 8 fertilized. I am awaiting to see how many live to blastocyst stage. I hear all of the statistics so tend to be rather negative.
Keity
Thank you for sharing. Your story really gives me hope (perfect timing 🙂 )
Jenny
Hi im 30 years old i had 2 frozen embryos transferred but result is negative. Have 1 more left hope it will work
Sandra Spencer
Hi Lorraine
Thank you for sharing your story . I am 44 next month just started ivf 2 eggs made it but on last day to be frozen didn’t make it . Any ideas how to increase your egg count for my next round of ivf
Sandra
Lisa
Hi,
It’s been 5 days since my fresh 2 blastocyst Transfer and I am spotting pink light discharge.
I am nervous as this is what happens prior to me getting my period. Was yours successful after spotting?
Thanks
Lisa
Angela
Lorraine, this is so beautiful story! I am 42, I live in Europe in Croatia, and here is very rare almost impossible for woman after 42 to give birth even with ivf. The procedure for ivf is different, not very successfully.. can you tell me please what stimulation protocol did you have? What is recommended there for older women for stimulation protocol And did you take something for egg quality?
Angela Smith
Thank you for sharing this. Appreciated. How did the transfer go?
Mira
Hi everyone,
My name is Mira and 29 years old. My husband and I just started our IVF journey. I was diagnosed with PCOS at the age of 20. I feel very nervous but my doctor seems very confident so it gives me peace of mind. I’m going to the IVF class this Thu and will starts Meds on Friday. So excited and scared at the same time. Hope it works out for us.
Mani mani
Hey….i knw its too late to answer but i hope u got gud results.oll d best
Sladja
Hey Mira I am just going trough and have seen you were starting your first IVF. How did you go?
Trisha
Hi Mira I know it’s quite late to ask you this but saw that you went thro ur first IVf how ws it?? Please let me know as even I wear gng thro the same I am on day 6 of my cycle with gonal F injections
Christie
I’m 30 years and I had my first ivf in June… had a frozen cycle but unfortunately the results were negative… so we decided to go for a second round and we got lucky and 2 blastocyst where transferred… today is Sunday and was due for pregnancy test last week Wednesday…truth is I’m so scared of what the results maybe… don’t think I can another disappointment but tomorrow morning will definitely buy a pregnancy test and just pray for the best
Dila
I am 31 years old from Singapore. I had 2 frozen day 5 blastocysts transferred yesterday (24oct2017). This is my second ivf cycle. My first ivf cycle was 2 years ago and it was successful with 1 frozen day 5 blastocyst transferred. What’s your results Christie? I will know my results on the 1st nov 2017. Wishing all the best to couples who are undergoing ivf now.
carla
How did it go Christie? praying for you <3
Faizr
Dila, which hospital you went for your IVF/ICSI?
My wife age 32 did her first IUI treatment at KKH, Singapore in May 2017 but unfortunately the results were negative. On September 2017, we did a ICSI 1 fresh day 5 blastocyst (Grade B2) transferred and again the results were negative.
Now we are left with 2 frozen day 5 blastocysts both in grade B2 with a good 92% thawing rate as mentioned by the embryologist and Dr Veronique Viardot. Our FET’s cycle will start next month and we decided to opt in for 2 blastocysts transfer. Hopefully it’s going to be a good success result. Any tips before or after treatment as in what to eat and what not to eat and etc?
Preeti
I had my blastocyst transfer on 13th july 2017. Now I have a negative result. On the day of transter after 5 hours I peed sitting on the floor. Was it a mistake on my part? Is it avoidable after embryo transfer?
Lady
Did u find out to ur doctor what went wrong?
anna
I had 2 day 6 FET implanted on June 8th.
I have no symptoms. It did not look like it was in blastocyst based on the picz online. It looks like a 14-16 cell morula.
I will find out Tuesday.
Tracy
Hi, did it work? Did you get a positive?
Cathy
Hi! I had 2 iui’s already. Last was 2014. I am now 39yo and getting ready for ivf. I prefer blastocyst (day5) embryo transfer than day2 embryo. Do you think day5 is really better to have likely outcome than day2 embryo transfer? I am nervous really. I’ve been wanting a baby for years.
Palak
Sir I m going for ivf next month with donor’s egg. I m 42. I prefer to go day 5 blastocyst transfer. But my dr. Said she will do one day 3 embryo transfer nd one day 5 blastocyst transfer. What do I do? Do I insist to do both blastocyst transfer?
Amanda conway
Hi was my first ivf and everything was good. My journey ivf. They said because off My age 41 now. I don’t have enough good eggs. So all my appointment was good scans. Didn’t have to up my injections. I had 2 good blastocyst put in last sun 10 days ago. Got test still this Friday. But I started to bleed monday. Got belly cramps. It feels like a period. Just can’t get my head around it. That everything was good
Beverley
I had day 3 embryo transfer on 11th may we had 7 survived eggs 5 had fertilised, we had 2 implanted and sadly the other 3 didn’t make the blastocyst stage so had to be disposed off , so feeling quite anxious as tomorrow we go for the blood test , this is our only chance
Cece
Hello,
I am turning 41 in a few days time, had 10 egg retrieval on the 16th may this year. It was very exhausting and I had so much pain. I have been taking paracetamol as advised but I signed up for e-freeze trial as I had 8 fertilised eggs and 5 good embryones at day 3. I am pre-scheduled for a transfer this Sunday for a day 5 blastocyst in case I change my mind about the e-freeze. My husband and I talked about it and we decided to go for fresh transfer subject to my feeling ok on Sunday. When I was informed by the embryologist that e-freeze has its own risk as there is a possibility that the egg may not survive the thawing process,
it made me think twice about the e-freeze trial cos I thought,what was the point of paying so much for my IVF and then miss the opportunity for a fresh transfer when am not even sure if the embryo will survive the thawing process if frozen. Just wondering, has anyone gone through the e-freeze trial for their first IVF? and if so, was the frozen successful? Many thanks
Jo
Hi Cece,
I am having the exact same thoughts and I’m not sure what to do. I also have signed up to the E-Freeze trial but am paying for IVF treatment. Studies seem to suggest a better outcome for FET’s but I am also worried that the embryos may not survive the feeding and thawing process. I think you have to go with your gut instinct maybe? x
Katie
Hi I had egg removal last year had 8 removed and all went under blastocyst. 5 survived but had to have these frozen as under went complications which ended up with me having to go under a operation. So a year later I was ready to have transfer of 2 eggs. Both eggs defrosted well one egg described as very good and the other egg described as in good condition! Had both transferred on Thursday and now just having the long wait until I do the pregnancy test! Fingers crossed. Hope this was helpful 🙂 x
cris
Yes. I had a frozen transfer of one day 5 blastcyst in January 2017. I am now 25 weeks pregnancy. I am 39 and this was our first ivf. We were very nervous because out of the 5 fertlized eggs we had, only 1 embryo made it to freeze. It was fortunately of good quality and survived the thawing process. We live in Las Vegas and our fertility doctor only does frozen embryo transfer. He is fantastic and has high success rates. I do recommend frozen transfers instead of fresh transfers. Your body is recovered from all the injections of the stimulation phase, and your uterus is more recetive to implantation. We are very happy and can’t wait for our miracle bean to arrive!
Christie
I’m 30 years old and 2 months ago I had a frozen cycle but unfortunately the results were negative… I just had another ivf done and I’m due for a pregnancy test… I’m hoping for all the best though I’m experiencing some pains
Lamora Gordon
I had a coworker that tried 3 cycles and her last embryo was frozen for 2 yrs..she is now 4 months pregnant.
Cris
Hi. I am 40 years old (two days to be 41) and after having an ectopic pregnancy late January I did a IVF transfer yesterday. 2 fresh 3 day type A embryos. Today I saw pink spotting in the toilet paper and then again brow spotting in the afternoon. I am a little bit concern as the transfer was just yesterday. I M having progesterone vaginal pills three times a day, aspirins once a day, folic acid plus lovenox 40 ( because I am trombopholic). Can you help in this matter please? Today is Saturday so my doctor is only available Monday. Thank you.
Heather
Hi Cris
I’m going to start ivf in 3 months. I am also 40. All of my blood work was excellent with high ovarian reserve and many follicles. So I’m optimistic that I will have many eggs to work with with great quality. I’m curious was everything ok with your transfer. Hoping that all was well
Xoxox
Jenny
I’ve heard that a day 5 blastocyst that is frozen, later thawed and transferred, is counted as being on day 6 on the day of transfer. Others have said that if it was frozen on day 5, the day it is thawed and transferred later on is still day 5. Can you clarify?
Keith
My wife just turned 40 and had 4 eggs retrieved from 4 follicles. 3 out of these 4 eggs after being fertilized matured to high grade blastocysts. These 3 were tested and then frozen for later implantation.
Maria
Ladies it’s ma first time and first cycle of IVF very nervous .. I’m on ma day 6 of day 5 embryo transfer.. I did a test yesterday which was day 5 after ma transfer but the results was negative do u think it was too early or didn’t work !!!
Jocelyn
it maybe to early
Amanda
Scheduled for my 2nd round on March 23,2016. I will have two 5 day blastocyst implanted. I prayer at least 1 takes. We don’t have anymore eggs in our basket. Happy thoughts 🙂
TK
Good luck!!
Tamara
I had 3 morulas transferred on 11th Dec ’15, Eggs were collected & fertilised on Monday 7th Dec. I was told to lie down for about 20mins after the transfer. I didn’t have anymore bedrest, but I took it easy, spent most of the day sitting down, reading my e-mails. However, I had a bumpy ride home, (driver hit a speed bump badly), I got a hard jolt. I got home & spent the weekend in bed, but I haven’t had any symptoms,. (today is day 8, after embryo transfer), I am getting jittery.
Terri Leigh
How did your transfer go. I hope it’s resulted in a healthy pregnancy so far x
butter
How did your transfer go? Hope it was successful.
Maria
How u doing tamara..I hope everything work out the way u wanted to ..,
charu
Sir, my 3 iui n 1 ivf got failed.now i m going for 2 ivf blastocyst with egg donor . My age is 31n my husband age is 34.my both tubes r patent and all the test are normal n et is also good but after facing so many failures i am totally hopeless now.plz tell me blastocyst is sucessful process.or i should go for some other treatment.
Thanks