I had a a fully hatched embryo placed and am 28+5 with identical twin girls. LBR was defined as the delivery of a live infant after 24 weeks of gestation. The usual way is by using the Gardner system, as I explained above. Aneuploid embryos tend to not implant, or fail to have sustained implantation. The embryos DNA comes together after the sperm and egg DNA combine during fertilization, but the resulting embryos DNA (genome) isnt ready yet. The second parameter refers to the inner cell mass (ICM), which develops into the fetus and is graded A to C. The third parameter refers to the trophectoderm, which develops into the placenta and is graded A to C. Hatching embryos are graded as a size 5 blastocyst. This post will mostly be with day 3 embryos in mind, but day 2 will be included where I can! Hatching Blastocyst. Ferreux L, Bourdon M, Sallem A, Santulli P, Barraud-Lange V, Le Foll N, Maignien C, Chapron C, de Ziegler D, Wolf JP, Pocate-Cheriet K. Hum Reprod. Like the ICM, trophectoderm quality depends on the number of cells and how cohesive and packed together they are. We discuss their journey and provide expert advice on finding support. Use of this site is subject to our terms of use and privacy policy. Check the full summary in my post Comparable outcomes with good quality day 6 and poor quality day 5 embryos. Live birth rate following frozen-thawed blastocyst transfer is higher with blastocysts expanded on Day 5 than on Day 6. VerMilyea. Read more about : Does ICSI Increase the Chances of Twins? 0000005244 00000 n I'm assuming they froze it that way, since it was only defrosted for a few hours before they transferred. But if youd like to learn more and better understand what youre looking at with your day 5 blastocyst picture, just send me an email! startxref I was googling for timelines after a 5dt to see when the embryo might actually implant. hatched blastocysts results in signicantly lower success rates when compared to other stages of blastocyst development (James, R. M et al, 2018). The blastocyst continues to develop until it reaches the hatching stage. Vacuoles are there fluid-filled pockets? IVF can be a tough road, but it's not one you need to walk alone. James et al. For people who meet the criteria for assisted hatching increased IVF success has been observed. 5-day blastocyst implantation timeline Successful implantation of the blastocyst in the uterus is necessary for the fetus to grow. Awadalla et al. 0000004204 00000 n Occasionally you might find that your embryos grade changes. IVF; blastocyst hatching; comprehensive chromosomal screening; implantation; preimplantation genetic screening; trophectoderm biopsy. (41. 0000003976 00000 n I've been scouring the internet looking for success stories of FET's with 4AA and 4AB blasts and am not finding any. 0000005130 00000 n Cytoplasmic pitting has a negative influence on implantation outcome. Heres an example of a embryo that has a thick zona (on the left), but you can see it hatching (on the right). Results: Of 676 euploid embryos included in this analysis, 464 were expanded or hatching (Ex/HgBl) and 212 were completely hatched (CHBl) at the time of transfer. 10/10/2018 15:08. Cent European J Urol. Remember the story about the tortoise and the hare. government site. Please specify a reason for deleting this reply from the community. (2022) found that these strings are more commonly seen in good quality embryos, and more strings indicated a higher chance for pregnancy or live birth rate. Oliva M, Briton-Jones C, Gounko D, Lee JA, Copperman AB, Sekhon L. J Assist Reprod Genet. endstream endobj 55 0 obj <> endobj 56 0 obj <> endobj 57 0 obj <> endobj 58 0 obj <> endobj 59 0 obj <. Researchers are divided whether this is a good sign or something to worry about. Aside is a picture showing an embryo which has survived the thaw and fully re . My clinic also does assisted hatching. I really hope it works out this time for you. Exactly what are day 3 embryos? D is for extremely poor ICMs. The hole is in the middle and you can see where its squeezing out: In this case the embryo was likely assisted hatched to prepare for PGT-A, because the zona is still thick. Usually its based on the fragmentation: The second number (4 in this case) is the number of cells. 0000003634 00000 n (2005). 0000002733 00000 n La Jolla Light. Wijnland Fertility grades embryos according to three parameters. Our embryo was a 6BB fully hatched. Most cleavage stage transfers these days are day 3 transfers, with fewer performing day 2 transfers. Assessment of embryo viability in assisted reproductive technology: Shortcomings of current approaches and the emerging role of mmetabolomics. 0000003181 00000 n In a few months I will be doing a natural FET. In some cases the expansion might change, or even the embryos quality. Blastocysts actually expand and contract (or collapse/compact) as a part of their normal development. Well also cover a bunch of research that goes over success rates for these embryos so you can get a general feel for how these embryos perform after transfer. If youre looking for positive signs after an embryo transfer to indicate that you successfully became pregnant, there are several notable ones. This discussion is archived and locked for posting. Biochemical pregnancy rate (BPR), implantation rate (IR), live birth rate (LBR) and early pregnancy loss (EPL) rate are similar in FH and NFH single euploid blastocyst embryo transfers. RESULTS: Of 698 FET's, 426 involved exclusively Day 5 embryos, 249 Day 6 and 23 Day 7. A Group Owner is a member that has initiated the creation of a group to connect with other members to share their journey through the same pregnancy & baby stages. Kinzer 2011 found that embryos that re-expanded more than 40% within two hours post thaw had a higher chance of implanting (~36% implantation vs ~10%). Uneven division may result in uneven distribution of proteins and other factors that the cell needs to develop normally (Rienzi et al. These strings connect the ICM and the trophectoderm cells, and its not clear what their function is. And lets not forget about day 2 embryos! Can't wait to hear good news from you on Friday. 1: Early blastocystthe blastocele is less than half the volume of the embryo. . If youre still confused after all of this and you want some extra help to understand your picture, I offer a service where I record a video and go over your picture for a fee. However, no studies have reported the possible effects of transferring cryopreserved blastocysts developed from poor-quality cleavage stage embryos on pregnancy and perinatal outcomes. Rhenman et al. 3 = partial expansion of the cavity filling at least 50% of the embryo. No additional funding was received. Other studies have found a similar impact of grades on euploids, including the impact of day 5, 6 and 7 (reviewed in my post on PGT-A (PGS) success rates). Many centers dont give a quality grade for the ICM or trophectoderm for early blastocysts (those with expansion 1 or 2). Eggs can be fertilized by conventional IVF or by intracytoplasmic sperm injection (ICSI). (847) 662-1818, 3800 Highland Avenue Suite 110 Downers Grove, IL 60515 0000058651 00000 n Because of inconsistencies in grading cleavage stage embryos, in 2007 the Society for Assisted Reproductive Technology (SART) began requesting its US clinic members to report data in a specific way (Racowsky et al. (2018)looked ateuploidembryos in women <35: So grading appears to give euploids a ranking order for transfer, just like what weve seen with untested embryos. Do the reproductive outcomes from the transfer of fully hatched (FH) blastocysts differ from those of not fully hatched (NFH) blastocysts? Terms are highlighted every 3rd time to avoid repetition. This isnt really a stage for an embryos development, but is when the egg is fertilized, or combined with sperm, as a part of IVF. Study design, size, duration: Different research has shown that embryos with better grades tend to have a higher chance of implanting and leading to a pregnancy. Every effort is made to provide accurate and up-to-date information. Over the next few hours the zygote has its first cell division to make 2 cells (once it becomes 2 or more cells, the zygote is called an embryo), and then another after about 24 hours to 4 cells, then to 8, etc. Embryos reach day 5 of development but havent hatched. Find advice, support and good company (and some stuff just for fun). Our website services, content, and products are for informational purposes only. National collection of embryo morphology data into society for assisted reproductive technology clinic outcomes reporting system: Associations among day 3 cell number, fragmentation and blastomere asymmetry, and live birth rate. We are here to answer any questions or concerns you may have so that you feel completely confident when taking the first step toward building your family. Huang et al. The babies began hatching Feb. 26 and continued through March 2, according to the aquarium, which is at UC San Diego's Scripps Institution of Oceanography. (2019)states It is estimated that embryos account for one-third ofimplantationfailures, while suboptimal endometrial receptivity and altered embryoendometrial dialogue are responsible for the remaining two-thirds. If youre having trouble getting pregnant, you might be considering IVF as a next step. Heres an example: Blastocysts are filled with water and sometimes this water escapes as the embryo grows in size. Some evidence suggests a hatching blastocyst is more likely to split into twins although other studies have found no significant increase. We respect everyones right to express their thoughts and opinions as long as they remain respectful of other community members, and meet What to Expects Terms of Use. How many day 3 embryos make it to blastocyst? I have only one left frozen.if it doesn't work then that's the end of my fertility treatments. As the embryo readies to burst through and implant itself in the lining of your uterus, the membrane of the ZP shell start to thin out. I have a friend who has identical pgd boys from her first pgd embryo that was also fully hatched. Heres a quick guide that puts it all together: Here are some pictures of day 3 embryos and their grades. What is the pregnancy success rate for frozen blastocyst embryo transfer in 32 yrs old woman? Think of this as studying the chemical fingerprints left behind by processes that happen in the cell. This uses a number followed by two letters, where the number indicates the embryos expansion (from 1-6) and the quality (A, B or C) of the inner cell mass (ICM) and trophectoderm. He second pgd transfer attempt was nearly fully hatched and is a singleton. Or is a 3BA better than a 3AB? It has also been suggested that the complete removal of the . Cytoplasmic strings are string-like structures that can be seen in an embryo photo. ICM quality depends on the number of cells and how compacted they are. 2 There are several theories on why this occurs, and one of those theories is that the embryo doesn't hatch properly. 0000017828 00000 n Hopefully, that one will pass through PGD and PGS. 0000002108 00000 n Inner cell mass (ICM) score, or quality - range A - C (A being the best) 3. Graph summarizes the same data for day of transfer and IVF outcome as in tables above This is an interesting comparison because many clinics would transfer a good quality day 6 embryo, but would discard a poor quality day 5 embryo. Some think it may be a way for the blastocyst to help the hatching process. Its based on two numbers, for example a 1/4: The first number (1 in this case) is the quality. I will not grade the embryo, since this is best done by your embryologist who had access to the microscope. 0000031408 00000 n A 1 can grow into 6 within a day. Therefore, we should expect success rates to be higher in this selected population as compared to the rates in unselected patients. You want a good amount of snow, and you want it tightly packed, otherwise it will fall apart. Yellow shows success rates for day 5 blast transfers Research shows that 8 is best. I'm having my FETon the 16th and the nurse told me that they will perform the assisted hatching after the thaw. 0000003069 00000 n Instead of air, the embryo is filled with water and gets bigger, or expands, over time. 0000013986 00000 n Think of the crumbs falling off that birthday cake. Others might only reserve the expansion 5 title for those that are naturally hatching (and not assisted). As an embryo develops to day 3, theres a chance the embryo will continue development, or will stop developing and arrest. 0000009955 00000 n Create an account or log in to participate. A cohort study of 1170 embryo transfers. XcPNPPI xX4Xp)770,`taj`Rqhd1ikMFffL5LbV41-+5 Both of these studies were done in PGS tested embryos that were biopsied. r. relyn2011. Day 7 embryos work check your clinics policy on discarding them. Capalbo A, Rienzi L, Cimadomo D, Maggiulli R, Elliott T, Wright G, Nagy ZP, Ubaldi FM. The best way to get accurate statistics will be from your clinic. Laser-assisted hatching is currently the safest, In cases where preimplantation genetic screening (PGS, preimplantation genetic testing for aneuploidy (, PGT-A), assisted hatching is one of the techniques used by laboratories, Embryos that have undergone hatching prior to biopsy have been. 0000001756 00000 n It is believed that assisted hatching can help an embryo implant in the uterus, leading to higher pregnancy rates in some patients. The site is secure. Before Secondary outcomes were also statistically similar between groups: BPR (65.9% versus 66.7%, OR 1.0; 95% CI: 0.6-1.6), LBR (43.1% versus 47.7%, P = 0.45, OR 1.2; 95% CI: 0.7-1.9) and EPL rate (22.8% versus 18.2%, OR 1.3; 95% CI: 0.7-2.4). Would love to hear what others have experienced when transferring a fully hatched embryo. 0000004764 00000 n air quality), Graded as excellent (AA) or good (AB or BA) = 50% live birth, Problems with the vaginal or endometrial microbiota, Anatomical issues (like polyps or fibroids), Immunological issues (autoimmunity, NK cells, T regulatory cells, HLA mismatching), The doctors and embryologists success rates. Both were FETs. The ZP has multiple functions, especially during the first few days of fertilization and development. 2022 Nov 24;37(12):2797-2807. doi: 10.1093/humrep/deac227. The Author 2016. A 4AA would be represented as 4-3-3, a 4CC as 4-1-1. The first parameter refers to the size of the blastocyst and is graded from 1 (smallest) to 5 (largest). In the video Ill also spend some time going over the parts of an embryo, embryo development and how grading works, using plenty of pictures to make sense of it all. Whats an A graded trophectoderm to one embryologist, may be a B to another (even from the same clinic). Authors:R.M. Bottom line: Its hard to know, based on grading alone, what your success will be. Theres quite a bit of data Ive compiled about these embryos, and you can check it out on my Grade C (poor quality) embryo success rates post. The ICM actually becomes the fetus, while the trophectoderm becomes the placenta! 2005-2023Everyday Health, Inc., a Ziff Davis company. There are two main types of cells in a blastocyst: the inner cell mass (ICM) and the trophectoderm. 0000009313 00000 n Heres a couple of studies: As well see, day 5 embryos tend to perform better than day 6 embryos, and He et al. Secondary outcomes were similar between groups: BPR (74.1% versus 72.9%, respectively, OR 1.1; 95% CI: 0.7-1.6), LBR (55.0% versus 50.0%, OR 0.8; 95% CI: 0.6-1.1) and EPL rate (18.9% versus 22.9%, respectively, OR 0.8; 95% CI: 0.5-1.2). Storr et al. 2014 Jun;29(6):1173-81. doi: 10.1093/humrep/deu033. So if youve gotten this far in this guide, it should be clear to you that embryo grades matter. acog.org/news/news-releases/2016/08/increased-success-and-safety-in-assisted-reproductive-technology-by-using-elective-single-embryo-transfer, ncbi.nlm.nih.gov/pmc/articles/PMC5987494/, The 30-Day Guide to IVF Success: Diet, Chemicals, Sex, and More, Everything You Need to Know About Artificial Insemination, Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT, Signs Your Embryo Transfer May Have Been Successful, How Fertility Treatment May Affect Your Mental Health. These two cell types are important when it comes to blastocyst embryo grading. Of these, 436 cycles entailed transfer of a NFH blastocyst (n = 123 fresh transfer, n = 313 frozen/thawed embryo transfer (FET)) and 372 cycles entailed transfer of an FH blastocyst (n = 132 fresh, 240 FET). March 4, 2023 11:43 AM PT. 0000005015 00000 n I transferred 2 in December- one fully hatched- in the picture i thought it was 3 embryos but it was the fully hatched embryo, the shell, and the 2nd embryo. Overall Blastocyst Quality, Trophectoderm Grade, and Inner Cell Mass Grade Predict Pregnancy Outcome in Euploid Blastocyst Transfer Cycles. Giulia et al. IVF outcomes in comparison to non-hatching embryos. The one thing we are sure about is that the grades given to an embryo gets dont necessarily seal its future. The individual cells that you were able to make out during the cleavage stage are harder to see during the morula stage because they start to merge with each other. Craciunas et al. In this case, you might just see a 1 or 2 as the grade and no letters. Materials and Methods: Pregnancy rates between the transfers of completely hatched blastocyst were compared to those of expanded or hatching blastocysts in 676 frozen single embryo transfer cycles occurring from January 2016 through December 2017. I get into this in more detail in the post Genetic analysis of arrested embryos reveals 3 distinct types. K. 0000004913 00000 n If eggs are fertilized right after the egg retrieval, then the day of the egg retrieval will be day 0. Disclaimer: These pages are meant purely for informational purposes. Here are some pictures of day 5 embryos (blastocysts) and their grades. As a result, it was common to transfer multiple embryos at a time, which usually meant that only the lowest-quality embryos were left over. This includes adjusting for maternal age, frozen embryo transfer protocol, endometrial receptivity, and methods of luteal support. They also check for fragmentation. Studies of blastocyst collapse in different species of mammals have found that most blastocysts, that experience consecutive weak contractions, hatch successfully whereas those that exhibit strong contractions or collapse, fail to hatch. 2017 found that while 10 experienced embryologist were able to consistently choose the best embryo for transfer, they werent consistent with grading. and the others all changed to BBs (some close to hatching). I had two hatching 5AA embies put back yesterday so know how you feel - just praying that implantation happens with these good quality embryos. This study is very interesting! These charts show the options for the number and each letter. The skin of the balloon is made up of the trophectoderm cells that surround a cavity called the blastocoel, which is filled with water. High quality day 5 blastocyst stage IVF embryoBlastocyst grading. Check it out to see a lot more! Good? a valuable technique to use in the laboratory for PGT-A cases. This is based on: This information can be gathered by examining the embryos under the microscope to give a grade which can be used as a ranking order for embryo transfer. Reminder: I have an integrated glossary in the text (terms are underlined with a dotted black line, and when you tap on it a window will pop up with the definition). More than 1.5 percent of all babies born annually in the United States are the result of ART or babies born from pregnancies that were possible thanks to assisted reproductive technology. There are a few techniques that can be used to perform AH and t. he most popular technique is by the aid of a laser. The other two I transferred were a day 6 morula (missed miscarried @6 weeks) and an ordinary day 5 blast (chemical). (2000)found that the highest rate of blastocyst conversion was with day 3 embryos with 7-9 cells and <15% fragmentation (~35%-40%). National Library of Medicine We have broken down the system we use for grading blastocyst success at ORM in the following chart: NUMBER: The degree of the expansion of the embryo's cavity, ranging from 2-6. @sprbaby2013, I looked, didn't see anything specific for hatching blastocysts just unspecified five day transfers. Accessibility Check it out to see a lot more! These embryos are assisted hatched, where the embryologist uses a laser to make a tiny hole in the zona. My acupuncturist mentioned that fully hatched embryos typically implant earlier. Bouillon et al. Similarly, there was no significant difference in fetal cardiac activity rates between Ex/HgBl and CHBl with morphologic grades BB and < BB (p=0.17). But if youd like to learn more and better understand what youre looking at with your day 3 embryo picture, just send me an email! Theres still a lot going on here that researchers arent sure about. Theres a reason embryos are graded. Racowsky C, et al. During the thawing process the embryo fully hatched from its shell prior to transfer. 2. Wider implications of the findings: Embryos were successfully frozen in the hatched or hatching state with resultant clinical pregnancies. Theres a lot of research that has shown that embryos across all grades are able to lead to healthy births. By transferring these embryos to patients, different studies have shown that lower quality embryos tend to result in fewer live births compared to high quality embryos. Patients selected for blastocyst transfer tend to be younger and have more embryos that look better under the microscope (better embryo quality). You can appreciate this by taking another look at the picture above and noticing how the ICM (around 9 oclock) is pretty hard to make out when the embryo is collapsed. Embryos are normally thawed in the morning but your transfer might not be until later in the day, which gives it time to continue developing. The sperms DNA is still highly compacted and decondensation needs to occur, as well as steps involved in reprogramming the embryos DNA so that genes involved in embryo development are activated. 0 - is a morula 1-2 - is an early blastocyst 3 - is a full blastocyst 4 - is an expanded blastocyst 5 - is a hatching blastocyst 6 - is a fully hatched blastocyst The first letter means how big the blastocyst is. This could change the grade that an embryo receives. (2023) found that poor quality day 5 embryos had comparable outcomes to day 6 good quality embryos. 0000021606 00000 n Good quality euploids tend to perform better than fair quality, which tend to perform better than poor quality. They found increases in miscarriage rates from day 5 to day 7, with decreases in live birth rate. Posted 6/26/14. In general, many cleavage stage embryos receive their grade based on the amount of fragmentation: Ideally when a cell divides they should both be the same size. There are a few techniques that can be used to perform AH and the most popular technique is by the aid of a laser. Federal government websites often end in .gov or .mil. Day 3 embryos are graded 1 to 4 (or 5) depending on the lab protocol with 1 being the highest grade. As fragments are lost, the cell that fragmented gets smaller. This cavity collects water and allows for the embryo to expand as it takes in more water. (2011). Did you perform PGS testing with the PGD? If half of the embryo has already done the hatching, the blastocyst will be graded as a 5, or when the embryo has completely finished the hatching, it will be graded as a 6. Which is comparatively high to the alternative freezing method called slow freeze with an 86% survival rate. Racowsky et al. They found that day 3 embryos with more than 10 cells had comparable implantation, pregnancy, live birth and multiple pregnancy rates compared to 8 cell embryos. 0000002302 00000 n This is crucial information to understanding embryo grading! At day 3, embryologists use a high-power microscope to take a look at the morphology (a fancy word for structure) of the embryo. Wondering if this could be possible twin pregnancy? More than 70 weedy seadragons have hatched at Birch Aquarium in La Jolla after a first-of-its kind egg transfer in the public eye. and transmitted securely. 4 studies showed the trophectodermwas predictive. 2005-2023 Healthline Media a Red Ventures Company. 2018 Mar 1;33(3):390-398. doi: 10.1093/humrep/dey004. I recall you are doing ivf to avoid passing genetic condition to offspring - which is same reason I'm here too. Leave the past behind: women's reproductive history shows no association with blastocysts' euploidy and limited association with live birth rates after euploid embryo transfers. There is always a chance that the embryo will not survive a thaw due to outside factors that cannot be controlled. Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available. All my embryos were CCS tested too, CCS and PGD are very similar. Limitations include the retrospective design and data from a single institution. Need help understanding your day 5 (blastocyst) embryo grade and picture? To date, no other study has evaluated the reproductive competence of an FH blastocyst transfer. Some studies show that embryos given higher grades result in better pregnancy rates and more live births, while lower-graded embryos result in poorer pregnancy rates and fewer live births, although this is not the case for all embryos. At least at my old clinic, the first number could vary based on factors besides fragmentation. Unable to load your collection due to an error, Unable to load your delegates due to an error, Clinical outcomes of not fully hatched versus fully hatched blastocysts in fresh and FET groups. Heads up: Blastocyst grading is complex and that means that grades arent carved in stone and may change. A blastocyst is a human embryo that's five or six days old. :). Here are 6 books that can support your IVF journey. There is fair evidence that nonfully hatched euploid blastocysts have a higher chance of implantation than fully hatched euploid blastocysts. Blastocystes were transferred to almost 90% of group 2 patients. We would definitely push for the blastocyst stage (day 5) due to the extra information that we get from the development from day 3 to day 5 (impact of the sperm dominance from day 3 onwards). DOI: Ebner T, et al. x. Advertisement | page continues below. Embryo grading is used during IVF to rank embryos for transfer after evaluating different parts of the embryo. Why did my embryo grade change after it was thawed? I just had a FET today. 2: Blastocystthe blastocele is greater than or equal to half of the volume of the embryo. Age is a critical factor as well as the endometrial environment where the embryo implants. In fact, this scenario (the presumably lower quality embryo resulting in pregnancy and birth) has played out many, many times. Prior studies have investigated the effect of paternal age on IVF success rates using donor oocyte cycles, which were summarized by a systematic review by Sagi-Dain et al. My RE automatically does assisted hatching prior to the implantation as some women have issues with the hatching process, plus it's one step closer to implantation which my RE said was a great thing. %%EOF 0000004386 00000 n In the second study there was a reduction in success rates, so this suggests the hatched embryo is more fragile. Its used as a way to rank embryos for transfer, with the better quality embryos having a higher chance of implanting compared to the lower quality embryos. 0000012309 00000 n Is there an optimal window of time for transferring single frozen-thawed euploid blastocysts? Embryo grading and IVF success rates. 0000004090 00000 n 0000009510 00000 n Becoming a blastocyst requires a massive shift in development. These were kind of house rules, and werent dictated by any studies that I know of. Generally, good quality embryos have a higher chance for live birth than fair quality, which have a higher chance than poor quality embryos. I have the full summary of this study on my post Predicting live birth rates, multiples based on 223,377 transfers. The 8 cell is a bit more challenging, because there are cells on top and below the plane of focus (where the microscope is focused). Archived discussions are usually a bit older and not as active as other community content. This takes into account the size the blastocyst, also called the expansion, the quality of the inner cell mass (ICM) and the quality of the trophectoderm. We avoid using tertiary references. This means that doctors can now transfer a single blastocyst with a good chance of success. Epub 2014 Feb 26. Dr. Michael Traub answered Fertility Medicine 20 years experience Varies: Assuming a good office and a good embryo and a normal uterus, if it is a routine embryo then pregnancy rate is about 40-45% and if it had genetic test. I know they perform assisted hatching on all the embryos before freezing them at the clinic I use. Same goes for blastocoel expansion rates. In some cases they are very small and may not be easily visible. Inactive. At this point, the blastocyst begins to prepare for implantation in the uterine wall. There are no conflicts of interest to declare.. Keywords: (2022) created models to predict live birth rates based on 223,377 embryo transfers in the US. PLoS One. This process usually takes a few days. You can see the graph below that shows the impact of cell number on predicted live birth after transferring a single fresh day 3 embryo.