IVF Embryo Development and Transfer Support: Naturopathic Support Before and During IVF

Supporting embryo development before transfer

By the time you reach embryo transfer, you have usually already been through a lot.

There may have been stimulation, egg collection, fertilisation updates, embryo grading and days of waiting to hear which embryos kept developing. If the numbers were lower than you expected, or an embryo stopped developing, it is very easy to come away thinking, “This must be my egg quality.”

But embryo development is not determined by the egg alone.

Both the egg and sperm contribute to what happens after fertilisation, and the way an embryo develops over those first few days can sometimes give us clues about where the difficulty may be sitting.

That is why I pay attention to the pattern across the whole cycle, not just the final number of embryos available for transfer.

Egg and sperm quality before IVF

When an IVF cycle produces fewer mature eggs, lower fertilisation or fewer embryos than expected, one of the first explanations many women hear is “egg quality”. It can leave you feeling as though the outcome was predetermined – particularly if age has also become part of the conversation.

Age and egg quality are important, but they are not the whole picture. Egg development can also be influenced by factors such as metabolic health, oxidative stress and nutrient status, while sperm contributes half of the embryo’s DNA and can influence fertilisation and early embryo development.

This is why I look at both egg and sperm factors when reviewing an IVF cycle, rather than assuming an unexpected result is automatically an egg issue.

You can read more about the factors I consider in my Egg and Sperm Quality page.

Fertilisation and early embryo development

If you started with a reassuring number of eggs but then watched the numbers drop at fertilisation, or were told that several embryos stopped developing before reaching blastocyst, it is natural to want to know why.

After fertilisation, the embryo begins dividing over several days before ideally developing into a blastocyst, usually around day five or six. Some attrition during this process is expected, which is why the number of eggs collected is rarely the number of embryos ultimately available for transfer or freezing.

When fertilisation is unexpectedly low or several embryos stop developing, however, there is not always one simple explanation. Egg factors, sperm factors, chromosomal abnormalities and aspects of the laboratory and treatment cycle can all play a role.

This is why the pattern across the cycle can be more useful than focusing on one number alone: where development slowed or stopped may help your fertility team decide what, if anything, is worth investigating before another cycle.

Embryo grading, PGT-A and embryo quality are not the same thing

You may have reached transfer with a beautifully graded embryo, been told everything looked promising, and then been completely blindsided when it did not implant. Or perhaps you only had a small number of embryos to begin with, and PGT-A left you with fewer – or none – considered suitable for transfer.

These are some of the hardest IVF outcomes to make sense of, because embryo grading, PGT-A results and an embryo’s actual potential are not quite the same thing.

Embryo grading assesses how an embryo looks and develops in the laboratory. PGT-A looks at chromosome numbers in a small sample of cells taken from the outer layer of a blastocyst. Both can provide useful information, but neither can tell us with certainty whether an individual embryo will implant and result in a healthy pregnancy.

This is particularly important when interpreting PGT-A. While it may help with embryo selection in some circumstances and can reduce miscarriage in some groups, it has not consistently been shown to improve the cumulative chance of live birth for every woman undergoing IVF. The small sample of cells tested may also not perfectly represent the embryo as a whole, particularly when mosaicism is detected, and healthy babies have been born following the transfer of some embryos reported as mosaic.

This is why I am cautious about reducing an embryo to a label of “good”, “bad” or “abnormal”. If you have very few embryos, or have been advised not to transfer an embryo because of a PGT-A result, it may be worth discussing what that particular result actually means with your fertility specialist or a genetic counsellor before making decisions about your remaining embryos.

And if a well-graded or chromosomally normal embryo has already failed to implant, that does not automatically mean there was something wrong with the embryo. It is also a reason to look at the next part of the picture – the environment that embryo was being transferred into.

Preparing the uterine environment for embryo transfer

It can be particularly confusing when you reach transfer with a good-quality embryo, your lining has been described as “perfect”, and yet implantation still does not happen. On paper, everything may have looked exactly as it should.

But preparing the uterus for an embryo involves more than reaching a particular endometrial thickness.

The endometrium needs to develop appropriately, respond to oestrogen and progesterone at the right time, and become receptive during the relatively narrow period when an embryo is able to implant. Structural conditions such as polyps or fibroids, and reproductive conditions including endometriosis and adenomyosis, may also become relevant depending on your individual history.

This does not mean there is always an identifiable uterine reason when a transfer fails. Sometimes even a well-graded or chromosomally normal embryo does not implant despite an apparently favourable uterine environment.

The aim is not to search endlessly for something that must be “wrong”, but to understand whether the important pieces of the uterine environment have been appropriately assessed – particularly when a transfer has not gone as expected.

Endometrial thickness and receptivity

If you have been through IVF, you may know your lining measurement almost as well as your hormone results. Watching it slowly increase at each scan – or worrying because it has been described as “thin” – can make that one number feel enormously important.

Endometrial thickness does matter. In general, very thin endometrium around the time of transfer is associated with lower pregnancy and live birth rates. But there is no single measurement that guarantees implantation, and pregnancies can and do occur with linings below commonly used thresholds.

Thickness also tells us only one thing about the endometrium. Your fertility team may consider its ultrasound appearance, how it has responded to oestrogen, the timing and duration of progesterone exposure, and whether there are uterine factors that could interfere with implantation.

So if you have been told your lining looked “perfect” but an embryo still did not implant, it does not necessarily mean something was missed. It simply means lining thickness cannot tell us the whole story about receptivity – which is why the timing of progesterone becomes another important piece of the transfer.

Progesterone timing and the implantation window

Sometimes a transfer can look right on paper – a good embryo, a good lining – and still not work. When I am looking back over a cycle like this, progesterone is one of the pieces I want to understand.

Progesterone helps turn the lining you have spent weeks building into an environment that is ready for an embryo to implant. In a medicated frozen transfer, the timing becomes particularly important because the embryo needs to arrive after the endometrium has had the right amount of progesterone exposure.

This is where you may hear people talk about the “window of implantation”. And if you have had a failed transfer, you may understandably wonder whether yours was somehow missed. There are tests that aim to personalise this window, but at this stage they have not clearly been shown to improve outcomes for most women when added routinely to IVF.

I also look at progesterone itself where appropriate. A serum progesterone result can be useful, but it is still a snapshot. Progesterone levels can fluctuate, the result can be influenced by how progesterone is being administered, and the amount measured in the blood does not necessarily tell us exactly what is happening at the level of the endometrium.

This is why I interpret progesterone in context rather than chasing one ‘perfect’ blood result. The IVF protocol, route and dose of progesterone, timing of the blood test and what happened during previous transfers can all help us understand whether progesterone deserves a closer look.

The point is not to find another thing to blame when a transfer fails. It is to make sure that, alongside the embryo and the lining, the hormonal timing of the transfer also makes sense.

Uterine conditions that may affect implantation

You may have been told that everything looks fine because your lining is thick enough and your scans have been reassuring. But when I am looking at implantation, lining thickness is only one of the pieces I consider.

Fibroids, polyps and hydrosalpinx are some of the more obvious factors. Depending on their size and location, they can interfere with implantation and may need to be addressed before transfer.

Chronic endometritis can also be relevant in some women, particularly after repeated implantation failure. This is persistent inflammation of the endometrial lining, often without obvious symptoms. Testing and diagnostic criteria are not completely standardised, so it isn’t something every woman undergoing IVF automatically needs to be screened for, but there are situations where it may be worth discussing with your fertility specialist.

I also pay close attention to endometriosis and adenomyosis. These conditions can be easier to miss, particularly when the symptoms don’t fit the picture you might expect.

For example, you don’t need to have debilitating periods to have endometriosis. Some women have subtle symptoms, symptoms they’ve lived with for so long they consider them normal, or very few symptoms at all. For others, difficulty becoming pregnant is one of the first reasons endometriosis is investigated.

This matters in IVF because endometriosis and adenomyosis may affect more than pain and heavy bleeding. They can influence inflammation, immune signalling and hormone response within the reproductive environment – all processes involved in implantation.

Having either condition certainly doesn’t mean an embryo won’t implant. But if your IVF history isn’t quite adding up, I don’t think they should be dismissed simply because you aren’t in significant pain.

This is where I like to put the pieces together – your symptoms, fertility history, previous scans and what happened during previous IVF cycles – and consider whether anything in the uterine or pelvic environment deserves a closer look with your fertility specialist.

Does inflammation affect IVF implantation?

If you have had a failed transfer, you may have come across the idea that inflammation is stopping your embryo from implanting. It is an understandable conclusion to reach, particularly when everything else seemed to look right.

But inflammation isn’t automatically a bad thing when it comes to implantation.

A carefully controlled inflammatory response is actually part of the process. The embryo and endometrium need to communicate with each other, and inflammatory signals help create the changes needed for an embryo to attach and begin implanting.

Your immune system is part of this conversation too. Immune cells within the endometrium help regulate inflammation and support the changes that happen around implantation. So the aim isn’t to suppress inflammation or immune activity altogether – both have a normal job to do. I will come back to the immune system in the next section.

What I am more interested in is whether something may be pushing this environment out of balance. Endometriosis and adenomyosis are obvious examples. Metabolic dysfunction, smoking and some underlying health conditions may also contribute to higher or more persistent inflammatory signalling.

Instead of assuming inflammation is the problem because a transfer hasn’t worked, I look for a reason it may be relevant. Is there a known condition that could be contributing? Are there symptoms or results that warrant further investigation? And is there something genuinely modifiable that we can work on alongside your IVF treatment?

Inflammation can absolutely be part of the implantation picture. The important question is not simply “Do I have inflammation?” but “Is there a reason inflammation may be out of balance in my particular case?”

The immune system and IVF implantation

If you have been told that your immune system may be “rejecting” your embryos, it can leave you feeling as though your own body is working against you.

But that is a very simplified way of describing what happens during implantation.

Your immune system is meant to be involved. Immune cells within the endometrium help the embryo and uterine lining communicate, regulate inflammation and support the changes needed for implantation and early placental development. The goal is not to switch the immune system off, but to have an appropriately regulated immune response.

Where things become more complicated is trying to work out whether immune dysfunction is actually contributing when IVF hasn’t worked. You may have heard about natural killer (NK) cells, cytokine testing, HLA matching or treatments such as steroids and intralipids. While these are sometimes offered after repeated failed transfers, the evidence for many of these tests and treatments is still uncertain, and an abnormal result does not necessarily tell us why an embryo did not implant.

That doesn’t mean I ignore the immune system. I look at it in context. Known autoimmune disease, endometriosis, adenomyosis, chronic inflammatory conditions and your wider health history may all give us useful information. Where there is a genuine medical reason to investigate further, that should be done alongside your fertility specialist or an appropriately qualified medical practitioner.

What I don’t want is for you to come away from a failed transfer believing your body has simply “rejected” your embryo. Implantation is a much more complex conversation between the embryo, endometrium, hormones and immune system – and understanding which part of that conversation may actually be relevant is far more useful than trying to suppress the immune system indiscriminately.

Vaginal and endometrial microbiome and implantation

You can do all the blood tests, have your lining carefully monitored and reach embryo transfer without anyone ever talking to you about your vaginal microbiome. In fact, you may not even know what a vaginal microbiome is.

But when we are thinking about the environment an embryo is being asked to implant into, I think it is an important piece to consider.

Your vagina is home to its own community of microorganisms, known as the vaginal microbiome. Ideally, Lactobacillus species do much of the heavy lifting. They help keep the vaginal environment acidic and make it harder for potentially problematic bacteria to take over.

Why does this matter for implantation? Because the vagina doesn’t exist in isolation from the reproductive tract above it. Research has linked vaginal dysbiosis and lower Lactobacillus dominance with less favourable fertility outcomes, including implantation outcomes.

And here is the part that can easily be missed – you don’t necessarily have symptoms when something is out of balance.

You might have no unusual discharge, odour, irritation or recurrent infections. Yet more comprehensive testing can sometimes identify low protective Lactobacillus, vaginal dysbiosis or potentially relevant organisms that you had no idea were there.

Mycoplasma genitalium, for example, can be asymptomatic and has been associated with reproductive tract disease and infertility. Ureaplasma species and Mycoplasma hominis have also been studied in relation to infertility and reproductive outcomes. Their role in implantation specifically is less certain, so finding one doesn’t automatically mean it is the reason an embryo hasn’t implanted.

You may also have been through extensive fertility testing without ever being checked for some of these organisms. This isn’t necessarily because something has been overlooked. For example, current Australian guidelines don’t recommend routine screening for some genital mycoplasmas in women without symptoms, so they may simply never have appeared on a standard pathology request.

This is one of the reasons vaginal health is something I routinely look at when supporting implantation. A more detailed vaginal microbiome assessment can show us the balance of protective bacteria, signs of dysbiosis and organisms that may warrant a closer look.

The endometrial microbiome is a little different. You may have seen tests claiming to tell you whether the bacteria inside your uterus are affecting implantation. It’s an interesting area, but one where I think we need to be careful. The science is still evolving, and we don’t yet know that routinely testing and treating the endometrial microbiome improves live birth rates.

So this isn’t about trying to create a “perfect” microbiome before transfer. It is about making sure vaginal health hasn’t been forgotten – particularly when an imbalance or infection can sometimes be there without giving you any obvious clues.

Blood sugar, insulin and metabolic health during IVF

You might look at a section on blood sugar and think, “This doesn’t apply to me – I don’t have diabetes.” But insulin resistance can develop long before blood glucose reaches the diabetic range, and the signs aren’t always obvious.

You may notice energy crashes after eating, strong sugar cravings, feeling shaky when you haven’t eaten or weight becoming harder to manage. Or you may feel completely well and only discover an issue when insulin and glucose are looked at more closely.

So what does this have to do with an embryo implanting?

Insulin is not just involved in blood sugar. When insulin levels remain elevated, they can affect hormone signalling, inflammation and the way cells respond to glucose. These changes may also influence the endometrium – including the molecular signals involved in preparing the lining for implantation. Research suggests that insulin resistance and poorer metabolic health are associated with less favourable reproductive outcomes, particularly in women with PCOS and metabolic dysfunction.

This doesn’t mean insulin resistance automatically makes your uterus “unreceptive”, or that improving your blood sugar guarantees implantation. The relationship is far more complex than that. But if insulin is one of the things disrupting the hormonal and inflammatory environment around the endometrium, it makes sense to identify it rather than focusing only on how thick the lining became on a scan.

And this isn’t about putting you on a restrictive “fertility diet” or trying to achieve perfect blood sugar. Often the useful information is much more practical – looking at glucose and insulin together where appropriate, how regularly you eat, whether meals contain enough protein and fibre, movement, sleep and the other factors influencing insulin sensitivity.

What matters is recognising whether metabolic health may be quietly influencing your fertility picture – and, if it is, working on the pieces we can actually change.

Can thyroid function affect embryo implantation?

Maybe your thyroid has already been checked. You had a TSH test, it came back within the laboratory range, and that was the end of the conversation. For many women, it is.

The problem is that thyroid hormones are doing much more behind the scenes than controlling your energy or metabolism. The endometrium has thyroid hormone receptors, and thyroid signalling is involved in the cellular changes that help create a receptive environment for implantation.

So if thyroid function is genuinely disrupted and nobody looks beyond that initial result, we may be leaving a potentially modifiable piece of the implantation picture unexplored.

That doesn’t mean every borderline TSH needs treating, or that thyroid dysfunction explains every failed transfer. The evidence is strongest when there is genuine thyroid dysfunction. The role of subtler thyroid changes and thyroid antibodies in implantation is less straightforward and needs more careful interpretation.

This is where context becomes important. A TSH result can be useful, but sometimes there is a reason to look at it alongside thyroid hormones, thyroid antibodies, previous results and what has been happening in your body more broadly.

You don’t need to become obsessed with achieving the “perfect” thyroid result before transfer. But you do want to know that a potentially important hormonal influence on implantation hasn’t been hiding behind a result that simply said “normal”.

When repeated embryo transfers don’t implant

One failed transfer is hard enough. When it happens again, the question often changes from “Why didn’t this one work?” to “What are we missing?”

And that is a reasonable question to ask.

You may hear the term recurrent implantation failure, but there isn’t one universally agreed number of failed transfers that suddenly means you have it. Age, whether embryos have been genetically tested, embryo quality and the number of transfers all change how an individual history should be interpreted.

What matters more is the pattern.

If several embryos have failed to implant, particularly when they have been considered good quality, it may be time to step back before simply repeating the same approach. That means reviewing the cycle from beginning to end and asking whether there is a plausible reason something deserves a closer look.

That might be an embryo or sperm factor. It might be progesterone exposure or transfer timing. There may be a uterine issue such as a polyp, fibroid or hydrosalpinx, or a condition such as endometriosis or adenomyosis that hasn’t previously been recognised. Metabolic, thyroid or vaginal health may also be relevant depending on your individual history.

But this is also where more testing isn’t automatically better.

After repeated failed transfers, it is easy to end up offered a long list of add-on investigations – immune panels, thrombophilia testing, receptivity tests and other increasingly specialised options. Some are useful in specific circumstances, but many haven’t been shown to improve outcomes when routinely used after implantation failure.

The aim isn’t to test everything because something must be wrong. It is to look back at what has happened, notice where the pattern doesn’t quite make sense, and investigate the things for which there is a genuine clinical reason.

Because when you have already put so much into IVF, the next step should ideally be informed by what your previous cycles have taught us – not simply be another attempt at exactly the same thing.

What I look at when supporting an IVF cycle and embryo transfer

By the time many women come to see me, they have accumulated an enormous amount of information – blood tests, scan results, medication protocols, embryo reports and sometimes several rounds of IVF – but still don’t really understand what happened or what those results mean for the next attempt.

I want to understand that story, but I also want you to understand it.

We start by going back through your cycle and looking at what happened at each stage – egg numbers and maturity, fertilisation, embryo development, your transfer and what happened afterwards. If you have been through more than one cycle, we can also look for patterns that may not be obvious when each round is viewed separately.

From there, we look at the wider factors that may be relevant to implantation in your particular case. Not because every possible marker needs testing, but because your history usually tells us where it makes sense to look more closely.

The aim is to come away with a clearer picture of what may be modifiable, what needs to be discussed with your fertility specialist, and what probably doesn’t need any more of your time or energy.