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Why Does IVF Fail With Good Embryos? Understanding Implantation Failure, Miscarriage & What Happens Next

IVF failure with “good” embryos can feel confusing and deeply disheartening. You’re not imagining it — this is one of the hardest parts of fertility care. There are evidence-based reasons why IVF fails, even with embryos that look strong under a microscope. Here, we’ll help you understand what might have happened, what your body does next, and what you can do moving forward.

Tassia O'Callaghan profile

Author

Tassia O’Callaghan

Reviewed by

Kayleigh Hartigan

20 min read

Updated 2 December 2025

Spotlight:

  • Even genetically tested embryos (PGT-A normal) can fail to implant — implantation is a complex biological interaction, not a single-step event.

  • Most IVF failures happen before implantation, often due to uterine factors, hormonal timing, inflammation, embryo competence, or surgical history.

  • Around 60–70% of first IVF cycles do not lead to a live birth, even with good-quality embryos.

  • A failed cycle does not mean future cycles will fail — many people conceive on their 2nd or 3rd attempt.

  • Recovery, review, and tailored next steps can increase success — especially when a clinic looks closely at previous cycles and adjusts the plan.

What is IVF failure?

IVF failure is an IVF cycle that doesn’t result in an ongoing pregnancy. Clinically, this can refer to several moments:

  • No viable embryos for transfer

  • No implantation after embryo transfer

  • A biochemical pregnancy, where a very early pregnancy shows on a blood test but doesn’t continue

  • A miscarriage after implantation

  • Failed embryo development or fertilisation, depending on the stage treatment reached
 

These outcomes are, unfortunately, medically common. The HFEA (the Human Fertilisation & Embryology Authority) notes that IVF is a step-by-step process where many things have to align, and treatment not working doesn’t mean your body did something wrong or that you’re out of options. [1]

Research shows that most IVF failure happens before a positive pregnancy test — in the implantation stage, rather than later in pregnancy. [2]

 

What is implantation failure?

Implantation failure means the embryo does not attach to the endometrium and begin developing — this can happen in IVF cycles and spontaneous (AKA ‘natural’ cycles). This can happen with embryos that look “good” or “high grade”, because visual grading cannot guarantee genetic normality or biological compatibility.

Implantation issues can include:

  • A mismatch between embryo readiness and the endometrial “implantation window”

  • Hormonal conditions that affect endometrial receptivity

  • Uterine factors like polyps or inflammation

  • Embryo development problems that are not visible under the microscope

How common is it for a first IVF cycle to fail

Sadly, it is common. In the UK, many people will not conceive on their first IVF cycle. Clinics often describe the first round as both treatment and diagnostic, because it shows how your body responds to stimulation, how eggs fertilise, how embryos develop, and how your endometrium responds to progesterone. [3]

Most clinics advise preparing emotionally for the first cycle not to work — not because of pessimism, but because the cumulative success rate rises over multiple cycles.

 

What percentage of good embryos implant?

Even high-quality embryos aren’t guaranteed to implant, with an implantation rate of around 35–55%, depending on age, embryo genetics, progesterone levels, transfer technique, sperm factors, and endometrial health. Morphology (embryo appearance) cannot confirm chromosomal health. [4]

Generally speaking, according to 2023 data from the HFEA, the pregnancy rate per embryo transferred was 36% — on the lower end of the implantation rate for ‘good’ embryos. This is because fertility clinics will aim to select the best quality embryos for transfer where available, according to their grading. [5]

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Why does IVF fail with good embryos?

This is the most common question after a failed IVF cycle. But the answer is rarely one single factor. Often, it’s a combination of embryo biology, uterine health, hormonal alignment, sperm quality, and timing.

Below are the strongest evidence-based reasons for IVF failure with good embryos.

 

Embryo-related factors (even when embryos look “good”)

Even embryos that have high grades in the lab carry hidden biological differences. Appearance is only one part of embryo potential, and many important factors remain invisible without genetic testing. Understanding these differences can make IVF feel far less mysterious.

  • Morphology vs. genetics: A “good” embryo is graded on how it looks: symmetry, structure and development pace. These features don’t reveal genetic health, which is a major driver of implantation potential. A chromosomally abnormal embryo can look completely textbook in the lab yet still be unable to continue developing. [6]

  • Mitochondrial function: Mitochondria give an embryo the energy it needs to grow through the earliest stages of life. If an embryo has lower mitochondrial activity, it may reach blastocyst stage but stall at implantation. This is one reason why even high-grade embryos can behave differently once transferred. [7]

  • Embryo–endometrium signalling: Implantation depends on a sophisticated “conversation” between the embryo and the endometrium. If inflammation, hormonal timing or uterine conditions interrupt these signals, the embryo may not attach or may detach early. This mismatch is common and does not reflect anything someone did wrong. [8]
 

Uterine and endometrial factors

The environment inside the uterus plays a crucial role in how well an embryo can implant. Even small structural or inflammatory changes can influence blood flow, hormonal response and the ability of the lining to support early pregnancy. Many of these issues are treatable once identified. [9]

  • The uterine lining is thin: Clinics often aim for a lining of around 7–8mm before transfer, because this tends to offer the best conditions. Some people conceive with thinner linings, but if yours consistently measures lower, your clinic may adjust your protocol or medications to support growth. [10]

  • Polyps, adhesions or fibroids: These can disrupt the smooth inner surface of the uterus and make it harder for the embryo to attach securely. Removing or treating them often improves success rates and is a routine part of IVF troubleshooting. [2,11]

  • Chronic endometritis: This is a low-grade inflammation of the uterine lining that can quietly interfere with implantation. It’s usually treatable with antibiotics, and many people go on to have higher implantation rates after treatment. [12]

  • Scarring from previous surgery: Procedures such as a D&C after miscarriage can create small areas of scar tissue that alter how the lining responds to hormones. A hysteroscopy can assess this and offer treatment if needed. [13,14]

  • Undiagnosed adenomyosis: Adenomyosis can affect blood flow and make the uterine muscle less receptive. Once identified, clinics may adjust the protocol, offer medication or recommend suppression treatment to improve implantation outcomes. [15]

 

Hormonal and timing factors

Hormones guide the endometrium through every step of implantation. When levels rise too early, too late or not quite enough, timing between the embryo and the uterus can fall out of sync. Many of these factors can be adjusted in your next cycle.

  • Progesterone levels: Progesterone transforms the lining into a receptive state. If levels don’t rise at the right moment, the implantation window can be mistimed, making it harder for the embryo to attach. Some clinics now check progesterone on the morning of transfer to fine-tune timing. [16,17]

  • Implantation window variability: Not everyone’s implantation window follows the same timeline. For a small number of people, it may shift earlier or later, which can affect transfer success. Tests like ERA are available, though evidence is mixed and they are best considered after repeated failures. [18,19]

Immune and inflammatory factors

The immune system helps the body recognise and support an embryo, but it needs to be in balance. Excess inflammation or untreated conditions can make implantation more difficult. Clinics focus on factors with strong evidence, so treatment remains targeted and effective. [20]

  • Diagnosed autoimmune conditions: Conditions such as thyroid autoimmune disease or lupus can influence implantation if not well-managed. When present, clinics often coordinate care with endocrinologists or immunologists to optimise outcomes. [21,22]

  • Inflammation linked to conditions like endometriosis: Endometriosis can create a more inflammatory environment around the uterus. Managing inflammation before IVF can support implantation and is often part of more personalised care plans. [23,24,25]

 

Sperm factors influencing embryo development

Sperm health continues to play a role long after fertilisation. Even when embryos appear high-quality, subtle differences in sperm DNA can influence how well an embryo progresses and implants.

  • DNA fragmentation: When sperm DNA is more fragmented, embryos may develop normally at first but slow down or stop at critical early stages. Testing can help guide treatment changes or lifestyle support. [26,27,28]

  • Blastocyst development: Sperm quality can affect the embryo’s ability to reach blastocyst stage, even in ICSI cycles. Ensuring the underlying sperm factors are addressed supports stronger embryo development in future cycles. [29,30]

 

Lifestyle, metabolic and systemic health factors

General health influences hormone regulation, inflammation, blood flow and egg and sperm quality. These factors are never about judgement — they’re about understanding how your body responds under treatment and what can support implantation in a practical, evidence-led way.

  • Thyroid levels: Thyroid hormones help regulate ovulation, early embryo development and implantation. Even mild thyroid dysfunction can influence IVF outcomes, so many clinics test and treat this proactively. [31]

  • Insulin resistance: When cells are less responsive to insulin, hormones involved in ovulation and implantation may be affected. Supporting metabolic health through medication, nutrition or exercise can improve the reproductive environment. [32,33]

  • BMI range: Clinics use BMI to understand medication dosing, hormone absorption and anaesthetic safety. It’s a medical tool rather than a measure of personal value, and support should always remain respectful and individualised. [34,35]

  • Vitamin D levels: Vitamin D influences immune balance and endometrial receptivity. Supplementing when levels are low is simple, safe and sometimes beneficial for implantation. [36,37]

  • Sleep quality, chronic stress and inflammation: Restorative sleep and manageable stress levels support hormonal stability. These lifestyle factors won’t “make or break” a cycle, but they can help your body handle medication and implantation more smoothly. [22,38,39]

 

Random biological variation

Biology never follows a perfectly predictable blueprint. Even in the most carefully planned cycle with excellent embryos and ideal conditions, implantation can still vary from person to person. This unpredictability reflects the complexity of reproduction, not your effort, your worth or your future chances.

Why do I keep having failed IVF?

Repeated failure is called recurrent implantation failure (RIF). There is no single definition, but many clinics use two or more failed transfers of high-quality embryos as a threshold for further investigation. [40]

When reviewing repeated failure, specialists may examine some of the most common causes:

  • Uterine structure (via hysteroscopy)
  • Chronic endometritis
  • Adenomyosis
  • Progesterone timing
  • Sperm DNA fragmentation
  • Embryo genetics
  • Lab conditions or transfer technique

How do you know when IVF has failed?

Knowing whether an IVF cycle has worked is rarely as simple as waiting for a single symptom. The only reliable confirmation comes from testing, which is why clinics encourage you to hold tight until your official test day.

Most clinics schedule their pregnancy test between 9–14 days after embryo transfer, depending on whether you had a Day-3 embryo or a Day-5/6 blastocyst. This timing allows enough days for hCG to rise if implantation occurred. Testing too early can give misleading results, which is why official guidance recommends waiting until the specified day for an accurate result. [1]

Here are the signs clinicians look for — and what they actually mean.

  • A negative pregnancy blood test at your clinic: This is the clearest indicator that implantation didn’t take place. Clinics measure hCG levels with a quantitative blood test because it’s more sensitive and more accurate than home testing, and it avoids false positives from trigger-shot hCG. The HFEA notes that pregnancy is confirmed by a rising hCG followed by ultrasound evidence of a gestational sac, so a consistently low hCG means implantation didn’t occur. [1]

  • A negative home pregnancy test close to your official test day: If you use a home pregnancy test on or just before test day (usually between 9 and 14 days post-transfer), it’s generally reliable. The NHS confirms that modern home pregnancy tests are highly accurate when used after a missed period or at the equivalent stage in an IVF cycle. [41]

  • Withdrawal bleeding once progesterone is stopped: After a failed cycle, bleeding typically begins when progesterone support is discontinued. This is known as withdrawal bleeding and is expected when the endometrium sheds. Timing can vary slightly depending on the type and dose of progesterone used in your cycle, anywhere from 1 to 7 days.

  • No period after IVF but not pregnant: Occasionally, people have a delayed period even after a negative test because ovarian stimulation and luteal-phase medications can temporarily disrupt natural hormone rhythms. Menstrual timing can shift after fertility treatment, especially in cycles involving high-dose stimulation. Your clinic can check repeat hCG levels or progesterone if you’re unsure. [3]

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Is it easier to get pregnant after failed IVF?

It can be. A cycle that doesn’t work still provides a huge amount of clinical insight, and that information helps shape a more tailored plan for your next steps. IVF isn’t a one-shot treatment; it’s a process that gets clearer with each round. Many people have higher chances in later cycles because their team now understands how their body responds and what may need refining. Cumulative live-birth rates increase across multiple cycles, reflecting the way treatment adapts over time. [1]

There are a few things that your failed IVF cycle can tell you about the potential for future treatments or pregnancies, too, which can be invaluable information, even if things don’t work out how you’d hoped this cycle:

  • How follicles responded: The first cycle shows whether the stimulation dose was right for you. Your clinic can adjust medication to improve the number or maturity of follicles in future cycles, which can raise the chance of creating strong embryos.

  • Fertilisation patterns: Seeing how eggs and sperm behave in the lab helps embryologists identify trends. For example, they may switch between IVF and ICSI or consider sperm-related testing if fertilisation was unexpectedly low.

  • Embryo development: Embryo growth rates offer clues about egg quality, sperm quality, and lab conditions. If the embryos stalled at a particular stage, the next cycle can be adapted — such as changing culture media, timing, or transfer stage.

  • Endometrial response to progesterone: Lining behaviour often differs between fresh and frozen cycles, and some people benefit from changing protocol. Your clinic may tweak progesterone timing or dosage to better support implantation based on what they learned.

  • Timing of implantation: A failed transfer can help clinicians fine-tune the timing of future transfers. Progesterone monitoring or a different approach to endometrial preparation may improve synchronisation between the embryo and the uterine lining.

 

How many rounds of IVF is average for success?

Many people need more than one cycle. The HFEA describes success as cumulative across multiple attempts, not limited to a single cycle. Across the UK, many people have success within 2 or 3 IVF cycles, and cumulative outcomes reflect this step-by-step refinement. [1,42]

Age, diagnosis, clinic expertise, and embryo quality all shape how many attempts someone may need, which is why there’s no single “typical” number that applies to everyone. For some, adjustments made between cycles — like a new protocol or transfer approach — can make later rounds more effective than the first.

How to prevent implantation failure

Even with the best preparation, implantation is never fully preventable or predictable — there’s no intervention that guarantees attachment of an embryo. What can make a meaningful difference is identifying and treating medical factors that are known to disrupt implantation, such as cavity abnormalities, inflammation or hormonal imbalance. Lifestyle and medical optimisation can support fertility treatment, but implantation still depends on biological processes outside anyone’s control. [42]

You can support implantation by focusing on factors known to influence outcomes:

  • Treating polyps, fibroids or adhesions

  • Screening for and treating chronic endometritis

  • Reviewing progesterone timing and dosage

  • Considering sperm DNA fragmentation testing

  • Checking thyroid and vitamin D levels

  • Addressing insulin resistance

  • Prioritising sleep, nutrition and metabolic health

Working closely with your clinical team ensures the focus stays on measures that have good scientific backing and are appropriate for your diagnosis. This kind of targeted care helps create the most receptive environment possible, while acknowledging the limits of what medicine can influence.

What happens next? Your options after a failed IVF

A negative cycle is a moment that often brings both grief and questions, and it’s completely normal to need time before deciding what comes next. There’s no single “correct” option after IVF doesn’t work — the right choice is the one that fits your circumstances, health, and emotional capacity. Treatment plans often evolve across cycles, and that people benefit from space, support, and a clear understanding of their options before moving forward.

Continuing with another IVF cycle

When you decide to continue treatment, your team will look closely at what the previous cycle revealed and how that information can shape a more personalised plan. Small adjustments can have a significant impact on outcomes, especially once your clinicians have real-world data on how your ovaries, lining, and embryos behaved.

Clinics may adjust:

  • Stimulation protocol
  • Lab techniques
  • Fertilisation method (ICSI vs IVF)
  • Embryo testing, if relevant
  • Progesterone timing
 

If you’ve had 3 failed IVF cycles, many clinicians will recommend a full review, possible protocol change, or a second opinion. This kind of deeper analysis helps ensure the next steps feel more targeted and less like guesswork.

Trying to conceive without treatment

Some people do conceive naturally after an unsuccessful IVF cycle, especially if their diagnosis doesn’t prevent spontaneous conception. Returning to timed intercourse, mild monitoring, or using ovulation prediction tools can be realistic options depending on age, sperm parameters, and the underlying cause of infertility. Natural conception is still possible for many people even after fertility treatment. [42]

Natural pregnancy after failed IVF

Spontaneous conception between IVF cycles does happen, and it’s often tied to clearer hormone patterns, lifestyle changes, and a better understanding of ovulation timing. A failed cycle can highlight when you ovulate, how your cycles behave, and which factors may support a natural attempt. While no route is guaranteed, it’s reassuring to know that this possibility remains open for some people.

Taking a break

Stepping back can be important for both your body and your emotional wellbeing. Ovarian stimulation, progesterone support, and the stress of anticipation all take a toll, and a pause can help you reconnect with yourself before starting again. NHS guidance recognises the emotional load of fertility treatment and supports access to counselling at any stage of care. [43]

Stopping treatment

If you find yourself at a point where continuing doesn’t feel right, you deserve care and support as you explore other paths forward. People often benefit from counselling, peer communities, or speaking with specialist charities who understand the realities of infertility. Reaching this decision is never a failure — it’s a thoughtful evaluation of what you need and what feels sustainable.

Should I change clinics after failed IVF?

Switching clinics can make sense if you want a different approach, more personalised support, or access to diagnostics not offered in your current setting. You might also consider a change if you feel your concerns haven’t been taken seriously or if you’re navigating complex implantation or miscarriage histories.

Seen Fertility’s clinic insights highlight which UK clinics have strong reputations for implantation failure, recurrent miscarriage and complex-case management. This kind of data can help you choose a team that aligns with your needs, values, and expectations for care.

Clinics known for managing complex cases include:

What failed IVF really means for your next steps

IVF failure, whether with ‘good’ embryos or whatever grade embryos are available, is medically common and emotionally challenging. It reflects the complexity of implantation biology and the many steps that need to align. You’re not alone, and there are clear reasons why this happens — reasons you can explore, understand and act on with the right support. There are always pathways forward, and with personalised treatment, many people do go on to have successful pregnancies.

Failed IVF FAQs

Can stress affect implantation?

Stress can influence sleep, appetite, and your nervous system, which can shape how your body responds during treatment. It doesn’t directly cause failed implantation, but feeling chronically overwhelmed can make recovery and hormone regulation more difficult. Support, rest, and practical coping strategies often help people feel more grounded through the two-week wait. [44]

Can sex after transfer cause failed implantation?

Many clinics allow sex after transfer once you feel comfortable, because penetration or orgasm does not dislodge an embryo. The embryo is already in the uterine lining long before any physical movement could affect it, and it’s protected by the uterus itself. Your clinic may advise avoiding sex only if you have specific medical risks such as bleeding, infection, or ovarian discomfort after stimulation.

Can cysts cause a cancelled IVF cycle?

Yes. Some types of ovarian cysts can affect hormone production, follicle development, or your response to stimulation. When a cyst produces hormones or takes up space on the ovary, clinics may delay or cancel a cycle to protect your safety and give you a better chance of creating follicles evenly in a future round. Many cysts resolve naturally, and a later cycle often proceeds normally. [45]

Is recurrent implantation failure treatable?

In many cases, yes. Once a clinic identifies potential reasons — such as lining issues, timing problems, sperm DNA fragmentation, chronic endometritis, or anatomical concerns — treatment can be tailored to support implantation more effectively. A team experienced in recurrent miscarriage or complex implantation issues can explore solutions step by step, helping you understand what’s happening and what can be adjusted in your next cycle.

What happens to your body after failed IVF?

Your hormone levels gradually return to baseline in the days after stopping progesterone. You may experience heavier or more painful bleeding, mood changes, fatigue, or bloating as your body processes the abrupt shift. Some people notice irregular periods after IVF failure for one or two cycles, while others return to their usual rhythm straight away. Emotionally, it’s common to feel flat or depleted — not because of anything you did wrong, but because the physical and emotional load of a cycle is significant. With time and the right support, your body and mind recalibrate.

What are the symptoms of IVF failure?

Many people have no clear signs at all, which can be emotionally challenging. Others may notice failed implantation symptoms such as cramping, spotting, or bloating that feel similar to a pre-period phase. Failed implantation bleeding or discharge can appear as light spotting, brown bleeding or small amounts of watery discharge as progesterone falls. These symptoms don’t confirm success or failure on their own, which is why clinics rely on pregnancy tests rather than physical signs.

When will I get my period after failed IVF?

Most people get their period 12–16 days after a failed embryo transfer, or a few days after stopping progesterone. A period after failed IVF can feel slightly different from your usual cycle because of the medication. Some people notice a painful or heavy period after failed IVF, while others experience brown bleeding after failed IVF as progesterone levels drop. If you have irregular periods after IVF failure or no bleeding at all, your clinic can check hormone levels and confirm what’s happening.

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