If you’ve experienced one or two miscarriages, it can feel frustrating and heartbreaking to hear doctors say, “We only start investigations after the third.” But there’s a reason behind this, and understanding it can help you feel a little more informed and empowered.
Why Do Miscarriages Happen?
The most common reason for early miscarriage is a problem with the baby’s chromosomes. These are the bits of DNA that carry genetic information. When an egg and sperm meet, they’re supposed to bring the right amount of chromosomes. But sometimes, especially as we get older, this process goes wrong.
Here’s the tricky part: as women, we’re born with all our eggs already inside us. Those eggs have been sitting there since before we were born! As we age, especially in our late 30s and 40s, those eggs are more likely to have trouble splitting their chromosomes correctly when it’s time to ovulate. This can lead to embryos with the wrong number of chromosomes—and unfortunately, most of those won’t survive.
After 3 Miscarriages: What Tests Can Be Done?
Once you’ve had 3 miscarriages, doctors usually offer more in-depth testing to see if something else might be going on. Here’s what they might look at:
Blood clotting issues – Thrombotic Risk Profile
Conditions like antiphospholipid syndrome can cause tiny blood clots in the placenta and stop an embryo from growing. Simple blood tests can check for this. It is called Thrombotic Risk Profile. Baby aspirin and heparin (a blood thinner) are sometimes used for clotting issues.
- Full Blood Count (FBC)
- Coagulation Profile 1
- Antithrombin III
- Factor V Leiden – G1691A Variant
- Factor II Prothrombin – G20210A Variant
- MTHFR – common C677T + A1298C variants
- Lupus Anticoagulant
- Protein C
- Free Protein S Ag
- Cardiolipin Antibodies (IgG+IgM)
Sperm DNA fragmentation
Even if a sperm test looks “normal,” the DNA inside might be damaged. High levels of DNA fragmentation have been linked to miscarriage. A special sperm test can check this. An andrologist would run this test.
Varicocele in men
This is when veins in the testicles are swollen. It can lead to higher sperm DNA damage. It’s treatable if found.
Thyroid problems
An underactive thyroid (even slightly) can increase miscarriage risk. Ideally, TSH (thyroid-stimulating hormone) should be close to 1 and definitely under 2.5. If your TSH is too high, you need to see an endocrinologist.
MTHFR gene mutation
This gene affects how your body uses folate (vitamin B9), which is crucial for cell division and healthy embryo development. If you have a mutation, your body might not process folic acid properly. The solution? Take the active form of folate (called methylfolate), so your body doesn’t have to do the work. A nutritionist specialised in fertility would help you take the right supplement.
Chronic endometritis
This is low-level inflammation of the womb lining. It’s hard to detect, but can sometimes be treated with antibiotics. A sonographer specialised in women’s health would help you detect it.
Immune issues
Sometimes, your immune system might react too strongly to a developing embryo. The embryo contains DNA from the father—technically “foreign”—and your body should normally adapt. But if this doesn’t happen, implantation might fail. In some cases, immune-modulating treatments like steroids or IV infusions can help. Dr Thum from the Lister clinic is a specialist. Steroids, intralipids, or IV immunoglobulins are used for immune issues (though not always offered on the NHS).
Uterus shape and structure
Some people are born with a uterus that’s divided (like a wall down the middle), or shaped in a way that can make it hard for a baby to grow. Scans can check for this.
Testing the Embryos
In France, testing embryos (like with a biopsy) is only allowed if a parent carries a known genetic condition. But in the UK, if you’re doing IVF privately, you can choose to test embryos for chromosome issues to reduce the risk of another miscarriage.
Karyotype testing (genetic tests for you and your partner)
Karyotyping checks the chromosome set of both partners to rule out underlying genetic abnormalities that could be causing fertility issues.
Who else can help?
If you have had 3 miscarriages, ask your GP to refer you to Dr. Raj Rai at St Mary’s Hospital in London. He is a leading experts on recurrent miscarriage.
Let me know if you have any questions,
All the best,
Silene
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