{"id":1096,"date":"2020-01-26T14:48:44","date_gmt":"2020-01-26T14:48:44","guid":{"rendered":"https:\/\/staging.theduff.co.uk\/?p=1096"},"modified":"2020-11-15T15:42:08","modified_gmt":"2020-11-15T15:42:08","slug":"day-3-vs-day-5-embryos","status":"publish","type":"post","link":"https:\/\/theduff.co.uk\/day-3-vs-day-5-embryos\/","title":{"rendered":"<strong>Day 3 vs Day 5 embryos:<\/strong> everything you need to know"},"content":{"rendered":"\n<p><strong>EMBRYO, EMBY, EMBABY, JOHN&#8230;<\/strong> whatever you choose to&nbsp;call those little multicellular diploid eukaryotic organisms, you can be certain&nbsp;they\u2019re going to take up a LOT of your headspace as you go through IVF.&nbsp;<\/p>\n\n\n\n<p>You\u2019ll have questions like\u2026&nbsp;<\/p>\n\n\n\n<ul><li>Why do some clinics transfer or freeze Day 3 embryos, while others transfer or freeze Day 5 embryos? <\/li><li>Which is better? <\/li><li>Why do some people talk about Day 6 transfers?&nbsp;<\/li><li>Why does no one ever want to transfer (or freeze) a Day 4 embryo?&nbsp;<\/li><\/ul>\n\n\n\n<p>This article attempts to answer them all! <\/p>\n\n\n\n<p><strong>A quick note about embryo grading&#8230;<\/strong><\/p>\n\n\n\n<p>You'll probably also want to know about embryo grading for Day 3 and Day 5 embryos. How is embryo grading performed? What does it tell us? Can it be trusted? What's a &#8220;good&#8221; embryo grade? What's a &#8220;bad&#8221; embryo grade? And so on. There's a separate article on all that called &#8220;<a href=\"\/embryo-grading-day-3-day-5\/\">Embryo grading for Day 3 and Day 5 embryos<\/a>&#8220;. <\/p>\n\n\n<style>.elementor-572 .elementor-element.elementor-element-189190b1{padding:0% 36% 8% 22%;}.elementor-572 .elementor-element.elementor-element-6b407887 > .elementor-element-populated{margin:0% 3.2% 0% 14%;--e-column-margin-right:3.2%;--e-column-margin-left:14%;}.elementor-572 .elementor-element.elementor-element-65191d58{--box-background-color:#FCFAEE;--box-border-color:#007595;--box-border-width:0px;--box-border-radius:0px;--box-padding:24px;--box-min-height:48vh;--header-color:#F16653;--toggle-button-color:#333333;--item-text-color:#007595;--item-text-decoration:underline;--item-text-hover-decoration:underline;--marker-color:#007595;}.elementor-572 .elementor-element.elementor-element-65191d58 .elementor-toc__header, .elementor-572 .elementor-element.elementor-element-65191d58 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0px;padding:0px 0px 0px 0px;}}\/* Start custom CSS for table-of-contents, class: .elementor-element-65191d58 *\/.elementor-toc__header-title {\n    color: #333333;\n}\n\n.elementor-toc__list-wrapper {\n    margin: 0em 2em 2em 0em;\n}\n\n.elementor-toc__list-items--collapsible li:not(:last-of-type) {\n    margin: 1.5em 0em;\n    padding-bottom: 1.5em;\n    border-bottom: 0.5px solid #007595;\n}\n\n\/* --- For Mobile --- *\/\n@media only screen and (max-width: 400px) {\n    .elementor-toc__list-wrapper {\n    margin: -1em 0em 0em 0em;\n}\n\n.elementor-toc__list-items--collapsible li:not(:last-of-type) {\n    margin: 1.2em 0em;\n    padding-bottom: 1.2em;\n    border-bottom: 0.5px solid #007595;\n}\n}\/* End custom CSS *\/<\/style>\t\t<div data-elementor-type=\"section\" data-elementor-id=\"572\" class=\"elementor elementor-572\" data-elementor-post-type=\"elementor_library\">\n\t\t\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element 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data-settings=\"{&quot;exclude_headings_by_selector&quot;:[],&quot;collapse_subitems&quot;:&quot;yes&quot;,&quot;min_height&quot;:{&quot;unit&quot;:&quot;vh&quot;,&quot;size&quot;:48,&quot;sizes&quot;:[]},&quot;headings_by_tags&quot;:[&quot;h2&quot;],&quot;minimized_on&quot;:&quot;none&quot;,&quot;marker_view&quot;:&quot;bullets&quot;,&quot;icon&quot;:{&quot;value&quot;:&quot;fas fa-circle&quot;,&quot;library&quot;:&quot;fa-solid&quot;},&quot;minimize_box&quot;:&quot;yes&quot;,&quot;hierarchical_view&quot;:&quot;yes&quot;,&quot;min_height_tablet&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]},&quot;min_height_mobile&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]}}\" data-widget_type=\"table-of-contents.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<div class=\"elementor-toc__header\">\n\t\t\t<h4 class=\"elementor-toc__header-title\">\n\t\t\t\tContents\t\t\t<\/h4>\n\t\t\t\t\t\t\t<div class=\"elementor-toc__toggle-button elementor-toc__toggle-button--expand\" role=\"button\" tabindex=\"0\" aria-controls=\"elementor-toc__65191d58\" aria-expanded=\"true\" aria-label=\"Open table of contents\"><i aria-hidden=\"true\" class=\"fas fa-chevron-down\"><\/i><\/div>\n\t\t\t\t<div class=\"elementor-toc__toggle-button elementor-toc__toggle-button--collapse\" role=\"button\" tabindex=\"0\" aria-controls=\"elementor-toc__65191d58\" aria-expanded=\"true\" aria-label=\"Close table of contents\"><i aria-hidden=\"true\" class=\"fas fa-chevron-up\"><\/i><\/div>\n\t\t\t\t\t<\/div>\n\t\t<div id=\"elementor-toc__65191d58\" class=\"elementor-toc__body elementor-toc__list-items--collapsible\">\n\t\t\t<div class=\"elementor-toc__spinner-container\">\n\t\t\t\t<i class=\"elementor-toc__spinner eicon-animation-spin eicon-loading\" aria-hidden=\"true\"><\/i>\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t\t\t<\/div>\n\t\t\n\n\n<h2 class=\"wp-block-heading\"><strong>Read this first!<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">The stages of embryo development<\/h3>\n\n\n\n<p>Everything in this article needs to be understood in the context of the development of the embryo \u2013 otherwise it just won\u2019t make sense. So allow me to take you on a fascinating tour of the contents of your doctor\u2019s petri dish\u2026&nbsp;<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><img fetchpriority=\"high\" decoding=\"async\" width=\"450\" height=\"299\" src=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-1.jpg\" alt=\"Embryo development Day 1 to Day 5\" class=\"wp-image-1124\" srcset=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-1.jpg 450w, https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-1-300x199.jpg 300w\" sizes=\"(max-width: 450px) 100vw, 450px\" \/><figcaption><em>(With thanks to https:\/\/www.utahfertility.com)<\/em><\/figcaption><\/figure><\/div>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Fertilisation<\/strong><\/h4>\n\n\n\n<p>When an egg is fertilised by sperm (whether in the fallopian tube or the petri dish), it becomes a \u201czygote\u201d. The zygote is a single cell that contains all 46 of the chromosomes needed to become a fully fledged human. A zygote is pretty much&nbsp;the first stage of human life.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>24 hours after fertilisation&nbsp;<\/strong><\/h4>\n\n\n\n<p>The new cell divides (\u201ccleaves\u201d) in two for the first time and it\u2019s no longer called a zygote: it\u2019s an \u201cembryo\u201d now. If you ever read about \u201ccleavage stage\u201d embryos, it\u2019s this stage \u2013 and the stage ends when the embryo becomes a \u201cblastocyst\u201d later on.<br> <br> In a \u201cnatural\u201d pregnancy, this embryo continues its journey through the fallopian tube towards the uterus, and divides in two yet again. In IVF cases, this all happens in the petri dish.&nbsp;<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Day 2 after fertilisation<\/strong><\/h4>\n\n\n\n<p>The cells of the embryo continue to divide in two. (In normal-developing embryos, cells divide every 18 to 20 hours.)&nbsp;<\/p>\n\n\n\n<p>Each of the cells is called a \u201cblastomere\u201d \u2013 and although they\u2019re dividing and therefore increasing in number, the embryo itself remains about the same size throughout the cleaving process. (Think of it like dividing up a pizza into two slices, then four slices, then eight slices.) <br> <br> Small portions of the cells may break off as they\u2019re dividing; this is called \u201cfragmentation\u201d, and it can negatively affect the quality of the embryo. More on this later. <br> <br> In a \u201cnatural\u201d pregnancy, all this happens while the embryo travels through the fallopian tube towards its final resting place in the uterus. With IVF, it happens in the petri dish.&nbsp;<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Day 3 after fertilisation<\/strong><\/h4>\n\n\n\n<p>The embryo is still busy cleaving at this stage. <\/p>\n\n\n\n<p>Depending on the clinic and the patient, some embryos are frozen or transferred on Day 3 \u2013 at this \u201ccleavage stage\u201d of development. If not, the embryo continues to develop in the petri dish\u2026&nbsp;<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Day 4 after fertilisation<\/strong><\/h4>\n\n\n\n<p>The embryo goes through something called&nbsp;\u201ccompaction\u201d, which is when the cells bind together&nbsp;tightly into a sphere. It\u2019s difficult to make head or tail of anything when looking at an embryo at this point,&nbsp;but that\u2019s fine and expected. It\u2019s now called a \u201cmorula\u201d, which is Latin for \u201cmulberry\u201d (because that\u2019s kind of what it looks like).&nbsp;<\/p>\n\n\n\n<div class=\"wp-block-image size-full wp-image-2289\"><figure class=\"aligncenter size-large\"><img decoding=\"async\" width=\"223\" height=\"223\" src=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-2.jpg\" alt=\"Day 4 embryo\" class=\"wp-image-1123\" srcset=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-2.jpg 223w, https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-2-150x150.jpg 150w\" sizes=\"(max-width: 223px) 100vw, 223px\" \/><figcaption>(With thanks to https:\/\/capefertility.co.za)<\/figcaption><\/figure><\/div>\n\n\n\n<p>If compaction doesn\u2019t start on Day 4, it\u2019s less likely that the embryo will develop into a blastocyst (see next step).<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Day 5 \/ Day 6 after fertilisation<\/strong><\/h4>\n\n\n\n<p>The embryo is now referred to as a \u201cblastocyst\u201d, and it\u2019s no longer dividing (\u201ccleaving\u201d). It consists of anywhere between 80 and 200+ cells, but no one\u2019s counting anymore because there are more interesting things to report. (And also because, I imagine, no one wants to sit there counting to 200 a few dozen times a day.)<\/p>\n\n\n\n<p>Fluid accumulates inside the blastocyst, causing it to expand in size, and the cells start to&nbsp;organise themselves into two groups: the \u201cinner cell mass\u201d and the \u201ctrophectoderm\u201d. There are therefore three distinct parts to the blastocyst: <\/p>\n\n\n\n<ul><li>The inner cell mass (ICM) \u2013 which is made up of cells that will go on to&nbsp;form the foetus<\/li><li>The trophectoderm (TE) \u2013 which is a layer of cells that will go on to&nbsp;become the placenta&nbsp;<\/li><li>The blastocoel, which is the fluid-filled cavity of the blastocyst<\/li><\/ul>\n\n\n\n<p>Here\u2019s what it looks like:&nbsp;<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><img decoding=\"async\" width=\"624\" height=\"246\" src=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-3.png\" alt=\"Day 5 blastocyst: inner cell mass, blastocoel and trophectoderm\" class=\"wp-image-1122\" srcset=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-3.png 624w, https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-3-300x118.png 300w\" sizes=\"(max-width: 624px) 100vw, 624px\" \/><figcaption>(With thanks to https:\/\/fertilitysolutions.com.au)<\/figcaption><\/figure><\/div>\n\n\n\n<p class=\"has-text-align-left\">Here\u2019s what it looks like in real life (\u201cC\u201d is the fluid-filled cavity, \u201cT\u201d is the trophectoderm, and \u201cICM\u201d is the inner cell mass):&nbsp;<\/p>\n\n\n\n<div class=\"wp-block-image size-full wp-image-2293\"><figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"360\" height=\"339\" src=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-4.jpg\" alt=\"Day 5 blastocyst in real life\" class=\"wp-image-1121\" srcset=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-4.jpg 360w, https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-4-300x283.jpg 300w\" sizes=\"(max-width: 360px) 100vw, 360px\" \/><figcaption>(With thanks to https:\/\/www.acfs2000.com)<\/figcaption><\/figure><\/div>\n\n\n\n<p>Note: some embryos are super keen and will reach blastocyst stage at Day 4. Embryologists reckon that blastocysts that form earlier (Day 4 or Day 5) have a higher likelihood of implanting than those that form later (Day 6 onwards) because they seem most \u201ceager\u201d to implant. That doesn\u2019t mean a Day 6 blastocyst <em>won\u2019t <\/em>result in a healthy pregnancy: not all embryos develop at the exact&nbsp;same time as each other, and many of them will still implant.&nbsp;&nbsp;<\/p>\n\n\n\n<p>Anyway! Back to our blastocyst. As it expands in size, the blastocyst also breaks down its protective outer membrane (called the \u201czona pellucida\u201d), to enable it to implant properly once it\u2019s in the uterus. This process is known as \u201chatching\u201d.&nbsp;<\/p>\n\n\n\n<p>Many embryos these days are frozen or transferred at this \u201cblastocyst stage\u201d. Some embryos will have already begun to hatch, while others will be on the verge of hatching.&nbsp;<\/p>\n\n\n\n<p>These images show the hatching process in action:&nbsp;<\/p>\n\n\n\n<p class=\"has-text-align-center\"><strong>Day 5 blastocyst (pre-hatching)<\/strong><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"245\" height=\"180\" src=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-5.jpg\" alt=\"Day 5 blastocyst \u2013 pre-hatching\" class=\"wp-image-1120\"\/><\/figure><\/div>\n\n\n\n<p class=\"has-text-align-center\"><strong>Hatching!<\/strong><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-6.jpg\" alt=\"Day 5 blastocyst \u2013 hatching\" class=\"wp-image-1119\" width=\"245\" height=\"183\"\/><\/figure><\/div>\n\n\n\n<p class=\"has-text-align-center\"><strong>HATCHED and ready to implant! (No more zona pellucida)<\/strong><\/p>\n\n\n\n<div class=\"wp-block-image size-full wp-image-2290\"><figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"245\" height=\"186\" src=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-7.jpg\" alt=\"Day 5 blastocyst \u2013 hatched\" class=\"wp-image-1118\"\/><figcaption>(With thanks to https:\/\/stanfordhealthcare.org&nbsp;for all three images)<\/figcaption><\/figure><\/div>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Day 7 \/ Day 8 after fertilisation<\/strong><\/h4>\n\n\n\n<p>\u201cEmbryo implantation\u201d happens. This is when the blastocyst fixes itself to an inner layer of the uterus called the endometrium. Not all embryos will be able to implant \u2013 due to both medical factors and pure luck \u2013 but those that do will take a further seven days or so to complete the implantation process.&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Transferring Day 3 vs Day 5 embryos<\/strong><\/h2>\n\n\n\n<p>In the past, almost all embryos would be transferred (or frozen) three days after successful fertilisation. Today, many clinics prefer to transfer or freeze the embryos five or six days after fertilisation instead \u2013 at blastocyst stage.&nbsp;<\/p>\n\n\n\n<p>There are many reasons why&nbsp;clinics prefer to transfer\/freeze embryos at blastocyst stage: <\/p>\n\n\n\n<ol><li>By the time the embryo has become a blastocyst, it\u2019s already survived a ton of developmental obstacles and is therefore more likely to survive the perilous journey from the doctor\u2019s petri dish to your uterus. (It\u2019s also more likely to survive the freeze-thaw process if it\u2019s being frozen.)<\/li><li>The embryo should have a stronger chance of implanting because it\u2019s a more natural time for the embryo to be in the uterus. (In a &#8220;natural&#8221; pregnancy, the embryo would still be travelling down the fallopian tube at Day 3 \u2013 and would reach the uterus around Day 5.)<\/li><li>As mentioned above, embryos that become blastocysts by Day 5 are more likely to result in healthy pregnancies than embryos that develop later. An embryologist can only know which are the \u201cspeedy\u201d blastocysts by monitoring them in the petri dish past Day 3. <\/li><li>\u201c<a href=\"\/embryo-grading-day-3-day-5\/\">Embryo grading<\/a>\u201d (a visual assessment of the embryo\u2019s \u201cmorphology\u201d, or appearance) is considered more accurate at Day 5 \u2013 when there\u2019s more to see and assess. The thinking goes that a Day 3 embryo could look fabulous (or atrocious), but there isn\u2019t enough information to go on \u2013 so Day 3 embryo grading might result in a sub-optimal embryo being transferred. <br> <br><strong><a href=\"\/embryo-grading-day-3-day-5\/\">If you're interested, I have an entire article about embryo grading<\/a><\/strong>.  <\/li><li>Another reason for favouring Day 5 embryos is more tangentially related to success rates: more and more clinics are experimenting with <a href=\"\/pgs-testing-ivf\/\">\u201cpre-implantation genetic screening\u201d (PGS)<\/a>, which in theory allows them to identify \u201ccompetent\u201d embryos that contain all 46 chromosomes. Clinics strongly prefer doing PGS on Day 5 embryos rather than Day 3 embryos. (You can read more about why that\u2019s the case <a href=\"https:\/\/www.remembryo.com\/pgs-testing\/#Day_3_or_Day_5_embryos_for_PGS_testing\">here<\/a>.) <br> <br>There\u2019s quite a lot of controversy around whether PGS actually helps to improve pregnancy\/birth rates. You can read all about it <a href=\"\/pgs-testing-ivf\/\">here<\/a>. <\/li><\/ol>\n\n\n\n<p>So\u2026 clinics\u2019 reasons for preferring Day 5 embryos sounds perfectly plausible in theory \u2013 to me, at least \u2013 but is there any evidence that transferring Day 5 embryos is more successful?&nbsp;<\/p>\n\n\n\n<p>Yes, there is. <a href=\"https:\/\/academic.oup.com\/humrep\/article\/20\/11\/3198\/2913825\">Here\u2019s just one study of many<\/a>. And here\u2019s the <a href=\"https:\/\/www.hfea.gov.uk\/media\/1783\/fertility-treatment-2014-trends-and-figures.pdf\">HFEA\u2019s report from 2014<\/a>, which reaches the same conclusion.&nbsp;<\/p>\n\n\n\n<p>Not all clinics agree with performing Day 5 transfers, however \u2013 and many continue to transfer (or freeze) Day 3 embryos for some or all patients. Their reasons are as follows:&nbsp;<\/p>\n\n\n\n<ol><li>Some clinics believe that the uterus is a better and\/or more natural environment for the embryo to grow and develop \u2013 so it\u2019s better for it to be moved there as soon as possible. <\/li><li>Linked to the above point\u2026 it\u2019s perfectly possible that an embryo <em>wouldn\u2019t <\/em>survive to Day 5 in the petri dish but <em>could <\/em>survive in the uterus if transferred at Day 3. <\/li><li>And linked to point (2)&#8230; If a couple ends up with just one or two embryos after IVF treatment, the clinic may decide it\u2019s better to transfer the embryo ASAP rather than hope and pray that it\u2019ll survive a couple more days in the petri dish. (I.e. it\u2019s better to put in a younger embryo than none at all.)<\/li><li>Some clinics might feel they don\u2019t have the most up-to-date technology to provide the best environment for growing (\u201cculturing\u201d) an embryo to Day 5.&nbsp;<\/li><\/ol>\n\n\n\n<p>And just as you\u2019d expect, some studies (like <a href=\"https:\/\/academic.oup.com\/humrep\/article\/15\/9\/1947\/2915370\">this one<\/a>) show that transferring Day 5 embryos <em>isn\u2019t <\/em>better than transferring Day 3 embryos.&nbsp;<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/Group-1285@2x.png\" alt=\"\" class=\"wp-image-492\" width=\"229\" height=\"105\" srcset=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/Group-1285@2x.png 443w, https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/Group-1285@2x-300x137.png 300w\" sizes=\"(max-width: 229px) 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.elementor-widget-container{margin:6% 0% 2% 0%;padding:0px 0px 0px 0px;}.elementor-291 .elementor-element.elementor-element-39ffc0a2{font-size:1em;}.elementor-291 .elementor-element.elementor-element-68569f9a .elementor-field-group .elementor-field, .elementor-291 .elementor-element.elementor-element-68569f9a .elementor-field-subgroup label{font-size:1em;}.elementor-291 .elementor-element.elementor-element-68569f9a .elementor-button{font-size:0.8em;letter-spacing:0.2px;border-width:0px 60px 0px 60px;}.elementor-291 .elementor-element.elementor-element-68569f9a > .elementor-widget-container{margin:-4% 0% 10% 0%;padding:0px 0px 0px 0px;}.elementor-291 .elementor-element.elementor-element-4e68b04a{font-size:1em;}}\/* Start custom CSS for button, class: .elementor-element-144e6175 *\/#fdg {\n    color: #FFFFFF;\n}\n#fdg:hover {\n    color: #FFFFFF;\n}\/* End custom CSS *\/<\/style>\t\t<div data-elementor-type=\"section\" data-elementor-id=\"291\" class=\"elementor elementor-291\" data-elementor-post-type=\"elementor_library\">\n\t\t\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-4c84a175 elementor-section-stretched elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"4c84a175\" data-element_type=\"section\" id=\"Mailing-list-sign-up-box\" data-settings=\"{&quot;stretch_section&quot;:&quot;section-stretched&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-554afbfb\" data-id=\"554afbfb\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t\t\t<section class=\"elementor-section elementor-inner-section elementor-element elementor-element-21014cc2 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"21014cc2\" data-element_type=\"section\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-inner-column elementor-element elementor-element-7c412ba7\" data-id=\"7c412ba7\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t\t\t<div class=\"elementor-element elementor-element-144e6175 elementor-align-center elementor-widget elementor-widget-button\" data-id=\"144e6175\" data-element_type=\"widget\" data-widget_type=\"button.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<div class=\"elementor-button-wrapper\">\n\t\t\t<a class=\"elementor-button elementor-size-sm\" role=\"button\" id=\"fdg\">\n\t\t\t\t\t\t<span class=\"elementor-button-content-wrapper\">\n\t\t\t\t\t\t<span class=\"elementor-button-text\">FREE DOWNLOAD<\/span>\n\t\t<\/span>\n\t\t\t\t\t<\/a>\n\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-1ed2b9df elementor-widget elementor-widget-heading\" data-id=\"1ed2b9df\" data-element_type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Questions to ask your doctor at every stage of IVF treatment: free downloadable guide<\/p>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-39ffc0a2 elementor-widget elementor-widget-text-editor\" data-id=\"39ffc0a2\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p><strong>IVF isn\u2019t just overwhelming<\/strong>; it can also be a mind-boggling and sometimes terrifying experience because there\u2019s so much to learn and so many rules to follow.<\/p><p>Problem is, doctors are busy \u2013 and they often don\u2019t have the time to anticipate your concerns and provide all the information you might need.<\/p><p>This downloadable guide contains questions that will help you understand the process better, get the answers you deserve, and feel more in control of the situation (and your rights as a patient).<\/p><p><strong>Enter your email address to receive it right away.<\/strong><\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-68569f9a elementor-mobile-button-align-center elementor-tablet-button-align-stretch elementor-button-align-stretch elementor-widget elementor-widget-form\" data-id=\"68569f9a\" data-element_type=\"widget\" data-settings=\"{&quot;button_width&quot;:&quot;20&quot;,&quot;button_width_mobile&quot;:&quot;100&quot;,&quot;button_width_tablet&quot;:&quot;25&quot;,&quot;step_next_label&quot;:&quot;Next&quot;,&quot;step_previous_label&quot;:&quot;Previous&quot;,&quot;step_type&quot;:&quot;number_text&quot;,&quot;step_icon_shape&quot;:&quot;circle&quot;}\" data-widget_type=\"form.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<form class=\"elementor-form\" method=\"post\" name=\"New Form\">\n\t\t\t<input type=\"hidden\" name=\"post_id\" value=\"291\"\/>\n\t\t\t<input type=\"hidden\" name=\"form_id\" value=\"68569f9a\"\/>\n\t\t\t<input type=\"hidden\" name=\"referer_title\" value=\"The Duff\" \/>\n\n\t\t\t\n\t\t\t<div class=\"elementor-form-fields-wrapper elementor-labels-\">\n\t\t\t\t\t\t\t\t<div class=\"elementor-field-type-email elementor-field-group elementor-column elementor-field-group-email elementor-col-80 elementor-md-75 elementor-sm-100 elementor-field-required\">\n\t\t\t\t\t\t\t\t\t\t\t\t<label for=\"form-field-email\" class=\"elementor-field-label elementor-screen-only\">\n\t\t\t\t\t\t\t\tEmail\t\t\t\t\t\t\t<\/label>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<input size=\"1\" type=\"email\" name=\"form_fields[email]\" id=\"form-field-email\" class=\"elementor-field elementor-size-lg  elementor-field-textual\" placeholder=\"Your email address\" required=\"required\" aria-required=\"true\">\n\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<div class=\"elementor-field-group elementor-column elementor-field-type-submit elementor-col-20 e-form__buttons elementor-md-25 elementor-sm-100\">\n\t\t\t\t\t<button type=\"submit\" class=\"elementor-button elementor-size-lg\">\n\t\t\t\t\t\t<span >\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\" elementor-button-icon\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-button-text\">Get the PDF<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/button>\n\t\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t<\/form>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-4e68b04a elementor-widget elementor-widget-text-editor\" data-id=\"4e68b04a\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p><strong>I won't send you spam. Unsubscribe at any time.<\/strong><\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t\t\t<\/div>\n\t\t\n\n\n<h2 class=\"has-text-align-left wp-block-heading\"><strong>Why aren\u2019t Day 4 embryos transferred?<\/strong><\/h2>\n\n\n\n<p>Here\u2019s what a Day 4 embryo looks like compared to all the other days:<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><img decoding=\"async\" width=\"223\" height=\"223\" src=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-2.jpg\" alt=\"Day 4 embryo\" class=\"wp-image-1123\" srcset=\"https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-2.jpg 223w, https:\/\/theduff.co.uk\/wp-content\/uploads\/2020\/02\/embryo-grading-2-150x150.jpg 150w\" sizes=\"(max-width: 223px) 100vw, 223px\" \/><figcaption>(With thanks to https:\/\/capefertility.co.za)<\/figcaption><\/figure><\/div>\n\n\n\n<p>Yes: it\u2019s a bit of a shitshow. It\u2019s just a mass of cells with no distinct features.&nbsp;<\/p>\n\n\n\n<p>This is the \u201ccompaction\u201d stage I referred to earlier \u2013 and it\u2019s when the cells bind together tightly into a sphere. It\u2019s hard to figure out what the heck is going on with Day 4 embryos: they can\u2019t be \u201c<a href=\"\/embryo-grading-day-3-day-5\/\">graded<\/a>\u201d using the methods used to grade Day 3 and Day 5 (or Day 6) embryos, so it\u2019s therefore difficult to decide whether they stand a chance of successful implantation. As a result, embryologists tend to leave them well alone.&nbsp;<\/p>\n\n\n\n<p>BUT some clinics (<a href=\"https:\/\/academic.oup.com\/humrep\/article\/23\/7\/1505\/733841\">like this one in Australia<\/a>) have reported success with creating their own \u201cgrading\u201d system for Day 4 embryos (as well as success in transferring them). The main benefits of being able to transfer Day 4 embryos are that it gives doctors and patients more flexibility and opportunities to transfer an embryo. Clinics in the UK might follow suit one day; we\u2019ll have to wait and see.&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Now learn about embryo grading<\/strong><\/h2>\n\n\n\n<p>Embryo grading is a largely subjective assessment of the &#8220;morphology&#8221; (the visual appearance) of embryos under a microscope. <a href=\"\/embryo-grading-day-3-day-5\/\">Read my article about embryo grading<\/a> if you want to learn the following: <\/p>\n\n\n\n<ul><li>What's the purpose of embryo grading? <\/li><li>What does it mean when an embryo has a good grade? <\/li><li>Does embryo grading discover chromosomal abnormalities too?<\/li><li>Day 3 embryo grading explained<\/li><li>Deciphering and understanding Day 3 embryo grades<\/li><li>Day 5 embryo grading explained<\/li><li>Deciphering and understanding Day 5 embryo grades<\/li><li>What's the &#8220;perfect&#8221; grade? <\/li><li>What\u2019s the lowest grade an embryologist would consider transferring?<\/li><\/ul>\n\n\n\n<p><strong><a href=\"\/embryo-grading-day-3-day-5\/\">Read the article about embryo grading here<\/a><\/strong>. <\/p>\n\n\n<style>.elementor-536 .elementor-element.elementor-element-3a6436ac{padding:4% 22% 8% 22%;z-index:2;}.elementor-536 .elementor-element.elementor-element-17d4eb46:not(.elementor-motion-effects-element-type-background) > .elementor-widget-wrap, .elementor-536 .elementor-element.elementor-element-17d4eb46 > .elementor-widget-wrap > .elementor-motion-effects-container > .elementor-motion-effects-layer{background-color:#C0E4E5;}.elementor-536 .elementor-element.elementor-element-17d4eb46 > .elementor-element-populated{transition:background 0.3s, border 0.3s, border-radius 0.3s, box-shadow 0.3s;margin:0% 14% 0% 14%;--e-column-margin-right:14%;--e-column-margin-left:14%;padding:2% 1% 4% 1%;}.elementor-536 .elementor-element.elementor-element-17d4eb46 > .elementor-element-populated > .elementor-background-overlay{transition:background 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