Recurrent Miscarriage: When to Investigate and What the Tests Mean

Losing one pregnancy is painful. Losing more than one can feel frightening and isolating. This guide explains, in calm and plain language, when investigation is recommended after repeated miscarriage, which tests are genuinely evidence-based, and what the results actually mean, so you can make informed decisions without fear or unnecessary tests.

What “recurrent miscarriage” actually means

Recurrent miscarriage, also called recurrent pregnancy loss (RPL) — is usually defined as the loss of two or more pregnancies before 24 weeks. The European Society of Human Reproduction and Embryology (ESHRE) uses this two-loss threshold, and counts losses whether or not they happened one straight after another. It is worth knowing that there is no single universal definition: some older guidance used three losses, which is one reason couples are sometimes told different things. In practice, most specialists now begin a structured evaluation after two losses. RPL affects roughly 1–2% of couples trying for a baby, so while it can feel very lonely, you are far from alone.

Why a single miscarriage usually isn’t a sign that something is wrong

Miscarriage is common: around 15–20% of recognised pregnancies end this way. The large majority of single, early miscarriages are sporadic — caused by a random chromosomal error at the moment of conception that was never compatible with a continuing pregnancy. These are not caused by working, exercising, lifting, stress, a previous contraceptive, or anything you did or didn’t do. This is why a first miscarriage does not normally need investigation. It is also why so much of the guilt women carry is, medically, misplaced. The picture changes only when losses repeat, because repetition raises the chance that an underlying, identifiable factor is contributing.

When investigation is recommended

Current ESHRE and American Society for Reproductive Medicine (ASRM) guidance supports starting a formal evaluation after two miscarriages. There are sensible reasons to look a little earlier in some situations, for example if you are in your late 30s or 40s, where the time available to act matters more; if a scan during a loss showed something unexpected; or if you have a known medical condition such as thyroid disease or a clotting disorder. The aim is a targeted assessment based on your history, not a long list of every test that exists. If treatment such as IVF or genetic testing of embryos later becomes relevant, that is considered separately, our page on recurrent pregnancy loss and IVF considerations covers that pathway in detail.

What the evaluation is looking for

A good recurrent-miscarriage workup looks across a small number of well-defined areas rather than testing for everything indiscriminately. Broadly, it asks: is there an autoimmune or clotting problem affecting the placenta; is there a hormonal or thyroid issue; is the shape or lining of the uterus contributing; is there a genetic factor in either partner or in the pregnancies; and are there lifestyle or age-related factors that can be improved. The sections below explain each of these and, just as importantly, which tests the evidence does not support.

Antiphospholipid syndrome, the most important treatable cause

Antiphospholipid syndrome (APS) is an autoimmune condition in which the body makes antibodies that promote tiny clots and interfere with the placenta. It is the single most important cause of recurrent miscarriage to identify, because it is the one for which treatment is clearly effective. Testing looks for three antibodies — lupus anticoagulant, anticardiolipin antibodies, and anti-β2-glycoprotein-I antibodies. A diagnosis requires the antibodies to be persistently positive, so an abnormal result is repeated after about 12 weeks before it is acted on. A single positive test is not, on its own, a diagnosis. When APS is confirmed, treatment substantially improves the chance of a successful pregnancy (see treatments below).

Thyroid and metabolic checks

Thyroid function (TSH) and thyroid antibodies (TPO) are checked because an overactive or underactive thyroid, and sometimes thyroid antibodies even with normal hormone levels, are associated with miscarriage. Overt thyroid disease should be corrected before and during pregnancy. Poorly controlled diabetes is another modifiable factor worth identifying and stabilising. These are simple, low-cost blood tests that occasionally reveal something genuinely correctable, which is exactly the kind of finding a focused evaluation is designed to catch.

Assessing the uterus, and why adenomyosis is now part of the picture

The shape and lining of the uterus are assessed with imaging, most often a 3D ultrasound or a saline-infusion scan, which show the cavity clearly. Where needed, hysteroscopy allows a direct look inside the cavity and can treat certain findings in the same sitting. The classic structural issue is a uterine septum (a dividing wall present from birth); polyps and adhesions are also looked for. A notable update in the 2022–2023 ESHRE guideline is that adenomyosis should now be assessed in women with recurrent loss, as evidence increasingly links it to pregnancy outcomes. Not every structural finding needs surgery, and the decision to operate is always weighed carefully against the evidence that it helps.

Genetic evaluation: pregnancy tissue and parental testing

Because chromosomal errors cause so many losses, genetic information can be very useful. Where possible, genetic testing of the pregnancy tissue (the products of a miscarriage) can show whether a particular loss was due to a chromosomal abnormality, which is often reassuring, as it points to a one-off event rather than an ongoing problem. Parental chromosome testing (karyotyping) is offered selectively rather than to everyone, typically guided by the tissue results or family history, because balanced chromosomal rearrangements in a parent are an uncommon but important finding. If a genetic factor is identified, options including IVF with genetic testing of embryos can be discussed as part of a wider fertility plan.

Tests that are commonly offered but not routinely recommended

An honest evaluation includes knowing what not to do. ESHRE specifically advises against several investigations being used routinely, because the evidence does not support them and they add cost, anxiety, and the risk of unproven treatments. These include broad inherited thrombophilia screening (reserved for those with a personal or family history of blood clots, or a research setting), natural killer (NK) cell testing and elaborate immune panels, and routine TORCH infection screening. Being offered a long, expensive panel of immune or clotting tests is, in itself, a reason to ask why each one is being done. Avoiding over-investigation and over-treatment is a core part of responsible care, not a shortcut.

“Explained” versus “unexplained” — and why unexplained is not hopeless

Even after a complete, guideline-based evaluation, no cause is found in around half of couples. Hearing “we couldn’t find a reason” can feel deflating, but it is better understood as “no dangerous, ongoing cause was found.” The reassuring reality is that the outlook for unexplained recurrent miscarriage is often genuinely good: a large proportion of couples go on to a successful pregnancy with supportive care and monitoring alone. Knowing this changes the conversation from “what is wrong with me” to “how do we give the next pregnancy the best, calmest possible start.”

Treatments that are supported by evidence

Treatment follows the cause. For confirmed antiphospholipid syndrome, low-dose aspirin combined with a blood-thinning injection (low-molecular-weight heparin) is the established, effective approach and markedly improves live-birth rates. Overt thyroid disease is corrected with appropriate medication. Progesterone deserves a careful word: it is not a universal cure. High-quality trials found no benefit from progesterone for unexplained recurrent miscarriage in women without bleeding; the evidence supports vaginal micronised progesterone specifically for women who have had a previous miscarriage and have bleeding in the current early pregnancy, which is also reflected in NICE guidance. Beyond medication, modifiable factors matter: stopping smoking and alcohol, reaching a healthy weight, taking folic acid, and stabilising thyroid or diabetes. Equally important is what to avoid, unproven immune therapies (such as steroids or intravenous immunoglobulin given routinely) are not recommended for unexplained loss.

The emotional side, and how we approach recurrent loss

Recurrent miscarriage is not only a medical problem; it is a grief that is often invisible to others. Good care acknowledges that. Our approach at Balaji Horizon Women’s Hospital is to listen to your history first, run a focused and evidence-based evaluation rather than an exhausting battery of tests, explain every result in plain language, and build an individualised plan, including early reassurance scans and supportive monitoring in the next pregnancy. Where fertility treatment or genetic testing becomes part of the plan, it is coordinated within the same team. If you have had two or more losses and want a clear, unhurried assessment, you are welcome to arrange a consultation.

Frequently Asked Questions

References

1. Bender Atik R, Christiansen OB, Elson J, et al. ESHRE guideline: recurrent pregnancy loss: an update in 2022. Human Reproduction Open. 2023;2023(1):hoad002. doi:10.1093/hropen/hoad002
2. Devall AJ, Papadopoulou A, Podesek M, et al. Progestogens for preventing miscarriage: a network meta-analysis. Cochrane Database of Systematic Reviews. 2021;4:CD013792. doi:10.1002/14651858.CD013792.pub2
3. Coomarasamy A, Devall AJ, Brosens JJ, et al. Micronized vaginal progesterone to prevent miscarriage: a critical evaluation of randomized evidence (PROMISE and PRISM). American Journal of Obstetrics & Gynecology. 2020;223(2):167–176. doi:10.1016/j.ajog.2019.12.006
4. Schreiber K, Sciascia S, de Groot PG, et al. Antiphospholipid syndrome. Nature Reviews Disease Primers. 2018;4:17103. doi:10.1038/nrdp.2017.103
5. National Institute for Health and Care Excellence (NICE). Ectopic pregnancy and miscarriage: diagnosis and initial management (NG126). Updated 2021.

Medically reviewed by Dr. Priyadatt Patel, MBBS, MS (Obstetrics & Gynaecology) — Senior Gynecologist · Advanced Laparoscopic Surgeon · IVF and Endometriosis Programme Lead, Endometriosis & Fertility Specialist, Balaji Horizon Women’s Hospital, Science City Road, Ahmedabad. Last reviewed: 23 June 2026.

This article is for general education and does not replace individual medical advice. Recurrent pregnancy loss needs assessment tailored to your history; please consult a qualified gynaecologist or fertility specialist about your own situation.