Embryo Arrest: 7 Factors to Review Before Your Next IVF Cycle
The fertilization report looked good. You had eggs. They fertilized. Day three looked fine.
Then came the call. Nothing made it past day five, or one did, and it was graded poor, and the cycle was over.
You were told it was egg quality. You were told it was a numbers game. You were told to try again.
If you are reading this in the days after that call, you are probably not looking for reassurance. You are looking for the part of the explanation that was left out. This article is that part.
Why the timing of embryo arrest changes where you look
An embryo does not run on one engine the whole way.
For the first two to three days after fertilization, development is directed almost entirely by what the egg supplied: the proteins, the messenger molecules, and the energy stored during the egg's final growth phase. Around the four to eight cell stage on day three, major activation of the embryo's own genome occurs, and the paternal contribution comes online.
That handover matters because it splits the investigation in two.
Embryo arrest before day 3 may point toward the egg and its energy
If development stalls in the first three days, the first place to look is the supply the egg packed in advance: mitochondrial energy, nutrient status, inflammation, and the metabolic environment the egg matured in.
Embryo arrest after day 3 may point toward the sperm and its DNA
If development looked strong on day three and stalled before the blastocyst, the first place to look is the integrity of the DNA the sperm contributed, along with oxidative stress on both sides.
Same line in the report. Two different first moves. Most workups examine neither. The protocol gets adjusted, and the cycle repeats.
We have written about this timing distinction in more detail in Embryo Arrest Day 3 vs Day 5 and The Day 3 Cliff. What follows is what to review before you cycle again.
The 7 factors to review before your next IVF cycle
1. The genome handover determines where the investigation starts
Before anything else is ordered, the embryology report should be read for timing. Where did development stop, and on which day. That single detail directs the entire workup. A report that shows strong day three development followed by blastocyst failure asks a different question than one showing arrest at the four cell stage.
2. The egg's energy supply was built before the cycle began
Reaching blastocyst is among the most energy demanding stages of early development. The embryo does not manufacture that supply. It inherits mitochondria from the egg and runs on what was packed in advance.
If nutrient status was depleted, if inflammation was elevated, if sleep and stress load were high during the final growth phase, the reserve the embryo inherits may be lower.
This is why adding CoQ10 alone may not shift the outcome. Absorption depends on gut function. Supplementation without testing can mean expensive supplements addressing a pattern that was never identified. We support egg energy by reviewing what may be depleting it, rather than by adding another bottle.
3. Sperm DNA fragmentation is not measured by a standard semen analysis
A standard semen analysis measures count, motility, and shape. It does not measure the integrity of the DNA inside the sperm.
Sperm carrying damaged DNA can fertilize an egg and produce a normal looking embryo on day two or three. Development can then stall after the handover, when the paternal genome is directing growth.
In a 2025 retrospective analysis of 870 fresh single blastocyst ICSI cycles, each one percent increase in sperm DNA fragmentation was associated with approximately 2.5 percent lower odds of obtaining a top quality blastocyst on day five. The same analysis found fragmentation was not predictive of clinical pregnancy outcomes.[1] That distinction matters. It speaks to why an embryo may have stalled, not to whether a pregnancy will occur.
The 2020 AUA and ASRM Male Infertility Guideline addresses evaluation of the male partner, and sperm DNA fragmentation testing remains an area where clinical opinion is not unanimous.[3] It is not an established diagnostic test for embryo arrest. It can provide context that a normal semen analysis cannot. More on this in our male factor pillar.
4. The full thyroid panel, including antibodies, not TSH alone
Thyroid function affects more than whether you ovulate. It is associated with the environment in which the egg develops.
Thyroid autoantibodies have been detected in follicular fluid at concentrations correlating with blood levels.[2] A complete panel may include Free T3, Free T4, Reverse T3, TPO antibodies, and thyroglobulin antibodies. We regularly see elevated antibodies in women with low AMH, repeated IVF failure, and pregnancy loss, including when TSH was reported as normal.
When TSH is elevated, thyroid medication may be part of the picture. On its own, it does not answer why the thyroid is off. Gut function, inflammation, and nervous system load are all worth reviewing alongside it.
5. Blood sugar and insulin, for both partners
Glucose and insulin regulation can shape the environment in which the egg matures and in which sperm are produced.
These patterns often sit beneath the surface in someone who feels well and whose routine labs are reported as normal. A single fasting glucose is a starting point, not a complete picture. Fasting insulin and HbA1c can provide context. Continuous glucose monitoring can show what a one-time draw cannot.
6. Inflammation, the gut microbiome, and oxidative stress
The same oxidative stress associated with sperm DNA damage is also associated with depletion of the egg's energy reserve. This is one review that applies to both partners.
Gut infections, food reactions, and dysbiosis are among the patterns we see most consistently and see missed most consistently. Stool testing can identify bacterial, parasitic, and fungal findings along with markers of intestinal inflammation. hs-CRP can provide additional context on systemic inflammatory load.
7. The 90-day and 74-day preparation window
The egg you ovulate next cycle completes its final growth phase over roughly the preceding 90 days. Spermatogenesis takes approximately 74 days.
A cycle that begins next month is being built on the basis of the environment of the last few months. If nothing in that environment has changed, the inputs to the egg and the sperm have not changed. This is the mechanism behind repeating a cycle and receiving the same result.
Waiting for its own sake accomplishes nothing. Reviewing the data during that window is a different proposition.
Markers we reference when embryos arrest
| Marker | Functional range we reference | Why it is reviewed |
|---|---|---|
| Ferritin | 80 to 100 ng/mL | Iron status supports oxygen delivery and cellular energy |
| TSH | 0.5 to 2.0 mIU/mL | Tighter than standard reference ranges |
| Free T3 | 3.4 to 4.4 pg/mL | Active thyroid hormone |
| Reverse T3 | Below 15 | Can be elevated under sustained stress load |
| TPO antibodies | Below 10 IU/mL | Thyroid autoimmunity, can be present with normal TSH |
| Thyroglobulin antibodies | Below 30 IU/mL | Reviewed alongside TPO |
| hs-CRP | Below 1 mg/L | Systemic inflammatory load |
| Fasting glucose | Below 86 mg/dL | Metabolic environment |
| Vitamin D | 60 to 80 ng/mL | Nutrient status |
| Homocysteine | 6.0 to 7.2 µmol/L | Methylation and nutrient status |
These are functional targets we reference, not diagnostic criteria, and they differ from standard laboratory reference ranges, which are built on disease thresholds rather than fertility optimization. They are not established diagnostic tests for embryo arrest.
Functional fertility review compared with a standard IVF workup
A standard workup is built to make treatment decisions quickly. It reviews AMH, FSH, antral follicle count, TSH, and a small set of baseline markers, then moves to protocol.
A functional fertility review reads the embryology report for timing, evaluates both partners, and examines the systems shaping egg and sperm development in the months before retrieval: gut and vaginal microbiome, food sensitivity, nutrient status, thyroid, including antibodies, metabolic markers, inflammatory markers, toxin exposure, and nervous system load.
We work alongside your medical team, not instead of them. We do not guess. We test.
Frequently asked questions about embryo arrest
Does embryo arrest mean I need donor eggs?
Not on its own. Embryo arrest describes when development stops, not why. The recommendation may have been made carefully. The question worth asking is whether the investigation behind it was complete.
My embryos looked good on day 3. Why did none reach day 5?
Grading assesses appearance, not the biology directing development. Arrest after day three occurs at the point where the embryo's own genome, including the paternal contribution, is directing growth. Sperm DNA integrity and oxidative stress are among the patterns worth reviewing at that stage.
My partner's semen analysis was normal. Does that rule out male factor?
A normal semen analysis reports count, motility, and shape. It does not assess DNA integrity, oxidative stress, inflammatory markers, blood sugar, or thyroid status.
Were my embryos chromosomally abnormal because of bad luck?
Chromosomal quality is not random. It is shaped by the egg's energy supply and the sperm's DNA integrity, both of which are influenced by the environment in the months before the cycle. That is information, not a verdict.
How long before another cycle should I start reviewing this?
The egg's final growth phase spans roughly 90 days, and spermatogenesis approximately 74 days, which is the window in which the inputs to the next cycle are being formed.
Stop repeating the cycle. Start reading the data.
If your embryos have arrested and you want to walk through what to review before the next cycle repeats the same result, we built the Embryo Audit Checklist for exactly this.
Download the Embryo Audit Checklist: https://fabfertile.com/pages/embryo-audit-checklist
If you want your cycle, your labs, your history, and your partner's picture reviewed together in one place, the Functional Fertility Second Opinion is a call where I do that with you. You leave knowing what your embryos may be indicating and what the next cycle will be built on. Whatever you decide afterward is yours, but it gets made with information your workup did not give you.
Book at https://fabfertile.com/pages/book
Related reading
- Embryo Arrest Day 3 vs Day 5: Egg Quality or Sperm DNA
- The Day 3 Cliff: Why Your Embryos Stopped Growing
- Male Factor Fertility: The Overlooked Variable in Embryo Outcomes
- Low AMH in Context
About the host
I'm Sarah Clark, founder of Fab Fertile and host of Get Pregnant Naturally, a podcast with over one million downloads. My functional fertility team works with couples navigating low AMH and failed IVF, reviewing functional lab results, gut microbiome, food sensitivity, vaginal microbiome, nutrigenomics, HTMA, DUTCH, toxin testing, and bloodwork alongside nervous system work, to help identify patterns that may not have been considered. We work alongside your medical team, not instead of them. Subscribe to Get Pregnant Naturally for weekly episodes on fertility optimization, IVF preparation, and the lab work your doctor probably isn't running.
Sarah Clark, founder of Fab Fertile, host of Get Pregnant Naturally (1M+ downloads), and author of Fabulously Fertile.
Last Reviewed: July 9, 2026
References
- Machałowski T, Machałowska J, Gill K, Ziętek M, Piasecka M, Mrugacz G, Ciepiela P. Sperm DNA Fragmentation Impairs Early Embryo Development but Is Not Predictive of Pregnancy Outcomes: Insights from 870 ICSI Cycles. International Journal of Molecular Sciences. 2025;26(16):7923. doi:10.3390/ijms26167923
- Monteleone P, Parrini D, Faviana P, et al. Female infertility related to thyroid autoimmunity: the ovarian follicle hypothesis. American Journal of Reproductive Immunology. 2011;66(2):108 to 114.
- American Urological Association and American Society for Reproductive Medicine. Diagnosis and Treatment of Infertility in Men: AUA/ASRM Guideline. 2020.
