Recurrent Miscarriage: The Testing That Often Gets Missed

What sits beyond the standard NHS panel, and why it matters

If you've experienced recurrent miscarriage and been through NHS investigations, you may well have been told everything came back normal. Standard recurrent miscarriage testing may include things like karyotyping, antiphospholipid syndrome and uterine structure, however there's a layer of physiology that sits outside it entirely.

What standard testing doesn't cover

Thyroid antibodies, even when TSH itself looks fine, are one of the more significant gaps. Research has linked elevated thyroid antibodies to a higher risk of early miscarriage independent of thyroid hormone levels, yet standard thyroid screening based on TSH alone can miss this completely. Subclinical nutrient deficiencies, blood sugar dysregulation, and gut-driven inflammation can all affect the uterine environment too, and none of these are part of a standard recurrent loss panel.

Thyroid antibodies (TPO), not just TSH

• Vitamin D, iron and B12 status
• Vaginal and uterine microbiome testing
• Fasting insulin alongside glucose
• Full luteal phase progesterone tracking, rather than a single day-21 blood draw
• Gut health and inflammatory markers

Thyroid antibodies and miscarriage risk

This one deserves more than a bullet point. Thyroid autoimmunity is present in a meaningful proportion of women with recurrent miscarriage, and elevated thyroid antibodies, particularly TPO antibodies, are linked to higher miscarriage risk even in women whose TSH sits comfortably within the normal range. The mechanism isn't fully settled, but a normal TSH alongside positive antibodies is a genuinely different picture to a normal TSH alone, and it's one that standard screening simply doesn't distinguish between.

Silent coeliac disease

Coeliac disease can sit undiagnosed for years without the classic digestive symptoms, presenting instead as fatigue, skin issues, or nothing obvious at all. NICE guidance recommends testing for coeliac disease in anyone with unexplained subfertility or recurrent miscarriage, and a Danish study of almost 70,000 women found meaningfully more miscarriages and stillbirths in the years before their coeliac diagnosis than after it. The standard NHS coeliac screen tests a single antibody, IgA tTG. A more comprehensive private panel tests eight antibody markers, which picks up cases the single NHS antibody can miss, including in people with IgA deficiency, where the standard test is unreliable on its own.

Vaginal dysbiosis and infections

The vaginal microbiome plays a bigger role in pregnancy loss than standard care accounts for. Bacterial vaginosis and broader vaginal dysbiosis are linked to a higher risk of both early and second-trimester miscarriage, and research has found that even chromosomally normal miscarriages are associated with vaginal dysbiosis and local inflammation, not just chromosomal factors. This is exactly why vaginal and uterine microbiome testing sits on the list above rather than as an afterthought. It's a genuinely modifiable factor, and one that's rarely tested for as part of routine recurrent loss investigations.

A word on progesterone specifically

This one comes up often. A single day-21 progesterone test tells you ovulation happened, but it's a snapshot, not a picture of the whole luteal phase. Progesterone needs to be sustained at an adequate level for roughly two weeks after ovulation to support the endometrium through implantation, and a single reading can miss a pattern where progesterone rises and then drops off too early. Full luteal phase tracking shows the shape of that curve, not just one point on it.

If you've had recurrent losses and been told everything is normal, that's often exactly the point at which a wider functional workup earns its place, because there's more to test than the standard panel was ever designed to cover.

Improve egg quality for Egg Freezing for a freshIVF  retrieval

Whether you're freezing eggs or heading into IVF, the eggs collected in any cycle began their final growth phase roughly 90 days before retrieval. That window is genuinely responsive to what you do with it. Here are the changes worth prioritising before a stimulation cycle.

Correct iron and vitamin D first

Both are common gaps, even in people eating well, and both play a direct role in hormone production and ovarian response. Low iron affects oxygen delivery to developing follicles, and low vitamin D is linked in research to poorer response to stimulation and lower quality embryos. Test both rather than guessing, and correct properly ahead of a cycle rather than starting supplementation the week before.

Bring alcohol right down

Alcohol is one of the clearer factors in the research. Studies link alcohol intake to reduced embryo quality during IVF, with as few as four drinks a week associated with a lower live birth rate in one study. In the run-up to a retrieval, cutting this right back matters more than almost anything else on this list.

Explore My Method

Cut back on sugar and processed food

Blood sugar spikes drive insulin up, and elevated insulin has direct effects on ovarian function and is linked to increased oxidative stress in the follicular environment where eggs mature. Swapping refined carbohydrates and processed food for whole foods, and pairing any carbohydrates with protein and fat, keeps insulin signalling steady through the stimulation window.

Add in antioxidants

The maturation process is vulnerable to oxidative damage, so antioxidant intake matters. Vitamin C, vitamin E, zinc and alpha-lipoic acid all have research behind them for supporting egg quality, and CoQ10 remains one of the most studied nutrients here, supporting the mitochondrial energy production eggs rely on heavily during maturation. A varied, colourful diet is the foundation, with targeted supplementation layered on where testing or diet suggests a gap.

Get good fats in, particularly omega-3

Omega-3 fats, found in oily fish, nuts and seeds, are strongly anti-inflammatory, and animal research links omega-3 intake to a slower rate of ovarian ageing. Good fats also support the hormone production that underpins a strong response to stimulation. Aim for oily fish a couple of times a week, plus nuts, seeds and olive oil daily.

Putting it together

None of these changes work in isolation, and the 90-day window is where they matter most. Start as early as you can before a planned cycle, and build these in steadily rather than all at once. Test iron, vitamin D and other core nutrient markers early, so you know exactly what you're correcting rather than guessing.

Explore Programs