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Repeated miscarriages: which tests help, and which don't?

6 November 2026, by Dr. Navdeep Singh Pannu

Repeated miscarriages: which tests help, and which don't?

Tests are worth discussing after two miscarriages. The European guideline (ESHRE, 2022) supports tests after two losses. The UK guideline (RCOG, 2023) defines recurrent miscarriage as three, but allows full tests after two when a cause is suspected. Both recommend antiphospholipid antibody and thyroid tests and a scan of the womb's shape. Neither recommends routine natural killer (NK) cell tests.

This page sets out what the two main guidelines say, where they differ, and which treatments have evidence behind them. The sources are listed at the end.

How many miscarriages before tests?

The two guidelines define it differently:

  • ESHRE (2022): recurrent pregnancy loss is "the loss of two or more pregnancies". The losses do not have to be one after the other. Ectopic and molar pregnancies are not counted.
  • RCOG (2023): recurrent miscarriage is three or more miscarriages in the first trimester. Doctors are encouraged to use their judgement and test after two if the losses seem to have a cause rather than being chance.

ESHRE reports that, defined as three losses in a row, recurrent miscarriage affects about 1 to 2% of women. It also says the risk of miscarriage is lowest between 20 and 35 and rises quickly after 40, and that there is no evidence that stress directly causes miscarriage. So don't blame yourself for ordinary stress at work or at home.

There is no Ministry of Health clinical practice guideline on recurrent miscarriage that we could find, so Malaysian specialists generally follow ESHRE and RCOG.

Antiphospholipid antibodies. Antiphospholipid syndrome (APS) is an immune condition that makes blood clot more easily, and it is a cause that can be treated. ESHRE strongly recommends testing for lupus anticoagulant and anticardiolipin antibodies after two losses, and says beta-2 glycoprotein I antibodies can be added. A positive result has to be repeated at least 12 weeks later to confirm the diagnosis.

Thyroid. Both guidelines recommend a TSH blood test and thyroid peroxidase (TPO) antibodies.

The shape of the womb. Both recommend checking every woman for a difference in the shape of the womb, such as a septum. A 3D transvaginal ultrasound is the preferred test. ESHRE added in 2022 that a standard 2D scan can also check for adenomyosis.

Lifestyle, for both of you. ESHRE recommends asking about the male partner's age, smoking, alcohol, exercise and weight too.

Which tests are used only in some situations?

  • Genetic testing of the pregnancy tissue. The RCOG says it should be offered after the third and later miscarriages, and after any miscarriage in the second trimester. ESHRE does not recommend it routinely but says it can help explain a loss. If you are miscarrying, ask whether the tissue can be sent for testing.
  • Chromosome tests (karyotype) for both partners. Not routine for everyone. The RCOG offers them when the pregnancy tissue shows an unbalanced chromosome change, or when no tissue result is available. ESHRE says they can be done after an individual assessment. If a rearrangement is found, both guidelines advise genetic counselling.
  • Sperm DNA fragmentation. Here the guidelines differ. ESHRE says it "could be considered". The RCOG says it should not be offered routinely outside research.
  • Inherited clotting disorders (thrombophilia). ESHRE suggests not testing unless there are other risk factors. The RCOG says women with a second-trimester loss may be offered tests for factor V Leiden, the prothrombin gene mutation and protein S deficiency, ideally in research. Neither recommends routine tests for MTHFR, protein C or antithrombin.
  • Prolactin, only if your periods are irregular or absent.

The guidelines advise against these as routine tests (the guideline is named for each):

  • NK cells, in blood or in the womb lining. ESHRE found "insufficient evidence" to recommend them. The RCOG advises against routine immune testing, including NK cells, cytokines and HLA, outside research.
  • Cytokines, HLA typing and anti-HLA antibodies (ESHRE).
  • Routine infection screening (RCOG).
  • Progesterone levels or other "luteal phase" tests, androgens, LH and homocysteine (ESHRE).
  • AMH and other ovarian reserve tests, not routinely (ESHRE). ESHRE found insufficient evidence linking low ovarian reserve to recurrent miscarriage.
  • Fasting insulin, fasting glucose or PCOS tests, done to predict the next pregnancy (ESHRE).

If you are offered a long panel of immune or clotting tests, it is fair to ask what each one would change.

Which treatments have evidence?

For antiphospholipid syndrome: aspirin and heparin. The RCOG recommends aspirin and heparin from a positive pregnancy test until at least 34 weeks, after discussing benefits and risks. ESHRE suggests low-dose aspirin from before conception and heparin injections from the positive test, for women with three or more losses. With only two losses, ESHRE suggests treatment within research.

For thyroid problems. An underactive thyroid (overt hypothyroidism) should be treated with levothyroxine. For milder, "subclinical" hypothyroidism the evidence conflicts. ESHRE says treatment may lower the risk, but benefits and risks should be weighed. If your thyroid works normally but you have TPO antibodies, ESHRE says levothyroxine should not be given, and the RCOG says it is not routinely recommended. ESHRE advises checking TSH again at 7 to 9 weeks of your next pregnancy.

Progesterone, if you bleed in early pregnancy. Two large UK trials changed practice:

  • PROMISE (2015): vaginal progesterone given from early pregnancy to women with unexplained recurrent miscarriage did not increase live births.
  • PRISM (2019): in women with bleeding in early pregnancy, progesterone made no significant difference overall. A benefit appeared in the subgroup of women with three or more previous miscarriages. Findings in a subgroup are less certain than a trial's main result.

The RCOG now says progestogen "should be considered" for women with recurrent miscarriage who bleed in early pregnancy. ESHRE says vaginal progesterone "may improve" live birth rates in women with three or more losses who bleed in a later pregnancy. The UK's NICE recommends vaginal progesterone for women with bleeding and a scan-confirmed pregnancy in the womb who have had a miscarriage before. ESHRE found insufficient evidence for progesterone given because of a "luteal phase" or low progesterone result, and PROMISE found no benefit for women without bleeding. Scotland's 2025 guidance does offer progesterone to women with four or more miscarriages even without bleeding, which shows that guidelines still differ. Don't start any medicine without your doctor.

Surgery for a uterine septum. The guidelines differ. The RCOG says it should be considered, ideally within audit or research. ESHRE notes that the one small randomised trial showed no benefit. For fibroids, ESHRE does not recommend removing those in the muscle wall, and says the evidence for removing fibroids or polyps inside the cavity is insufficient. See keyhole surgery and fibroids, adenomyosis and fertility.

For a chromosome rearrangement. After genetic counselling, the options include trying naturally, with testing in pregnancy if you wish, or IVF with PGT-SR to choose embryos. ESHRE notes the evidence that PGT-SR improves live births is limited. See PGT in Malaysia.

For second-trimester losses. If a weak cervix is suspected, ESHRE recommends serial scans of the cervix in the next pregnancy and says a stitch (cerclage) could be considered.

Healthy habits. The RCOG advises a BMI between 19 and 25, stopping smoking, limiting alcohol and keeping caffeine under 200 mg a day.

For unexplained recurrent miscarriage, the guidelines advise against:

  • aspirin or heparin, which do not improve live birth rates when there is no APS (ESHRE and RCOG);
  • steroids such as prednisolone (ESHRE);
  • intralipid, G-CSF and endometrial scratching (ESHRE: not enough evidence);
  • lymphocyte immunisation therapy, which ESHRE says should not be used because it does not work and can cause serious side effects;
  • routine PGT-A: the RCOG says there are "insufficient data to support the routine use of PGT-A" for unexplained recurrent miscarriage.

One treatment remains uncertain. ESHRE says repeated high-dose intravenous immunoglobulin (IVIG) very early in pregnancy "may improve" live birth rates in women with four or more unexplained losses, but more trials are needed.

What if no cause is found?

This is common. ESHRE estimates that 40 to 50% of recurrent miscarriage remains unexplained. That is hard to hear, but it is not bad news in itself: ESHRE bases the outlook on your age and your full pregnancy history, not on a test result.

The RCOG recommends supportive care, ideally in a dedicated recurrent miscarriage clinic. ESHRE describes what helps: time for questions, honesty, a shared plan, and easy access to your team in the next pregnancy, with early scans if you want them. Grief after miscarriage is real for both partners. See recurrent miscarriage care and mental health during fertility treatment.

Sources

This page is general information, not medical advice.

This article is for general education only and does not take your personal circumstances into account. Please speak to your doctor for a diagnosis and treatment that are right for you. Disclaimers