# Recurrent pregnancy loss > Recurrent pregnancy loss: how it is defined, which tests guidelines recommend, which treatments have evidence behind them, and what is known about the outlook. Source: https://www.ghinashami.com/en/interests/recurrent-pregnancy-loss/ Updated: 2026-10-13 Step 4 of 4 · When treatment has not worked Losing a pregnancy is painful, and losing more than one can be frightening. This page explains how recurrent pregnancy loss is defined, which investigations international guidelines recommend, which treatments have evidence behind them, and what is still unknown. - 5 min read - Reviewed 13 October 2026 - 4 references ## How it is defined The [ESHRE guideline](https://www.eshre.eu/Guidelines-and-Legal/Guidelines/Recurrent-pregnancy-loss) defines recurrent pregnancy loss as the loss of two or more pregnancies, not counting ectopic or molar pregnancies, and estimates that it affects around 1 to 2 percent of couples. The [RCOG](https://www.rcog.org.uk/guidance/browse-all-guidance/green-top-guidelines/recurrent-miscarriage-green-top-guideline-no-17/) in the UK uses three or more first-trimester miscarriages, but encourages fuller evaluation after two when the losses may have an underlying cause. Guidelines also differ on whether the losses must be consecutive. Age is a key factor: women over 40 have a higher risk of recurrent loss. ## Who it is relevant to - Women who have had two or more pregnancy losses - Couples who have had more than one loss after IVF - Women who have had a loss in the second trimester - Couples whose losses have had no explanation so far and who want to understand what is known ## What guidelines recommend investigating **Antiphospholipid antibodies.** Testing for lupus anticoagulant and anticardiolipin antibodies is recommended: by ESHRE after two losses, and by the RCOG before a next pregnancy. Antiphospholipid syndrome is one of the few findings with a treatment that guidelines support. **Thyroid.** Thyroid-stimulating hormone (TSH) and thyroid peroxidase (TPO) antibodies are recommended, with further thyroid tests if they are abnormal. **The uterus.** A transvaginal 3D ultrasound is the preferred way to look for a congenital difference in the shape of the uterus, such as a septum. The 2022 ESHRE update adds that a 2D ultrasound can look for adenomyosis. **Chromosomes.** ESHRE does not recommend routine genetic testing of pregnancy tissue but allows it for explanatory purposes; the RCOG advises offering it from the third miscarriage, and for any loss in the second trimester. A karyotype of both partners is suggested after an individual assessment of risk (ESHRE), or when the pregnancy tissue shows an unbalanced chromosome change or could not be tested (RCOG). See [genetic testing](https://www.ghinashami.com/en/interests/genetic-testing/). **Lifestyle, for both partners.** Smoking, alcohol and weight; for the male partner, also age and exercise. ESHRE suggests that sperm DNA fragmentation testing can be considered, while the RCOG advises against routine testing outside research. **Not routinely recommended.** Screening for inherited thrombophilia (unless there are other risk factors), immune tests such as natural killer cells, HLA and cytokines, and infection screening. ESHRE also advises against prolactin testing without symptoms, and against testing for PCOS, fasting insulin or glucose to predict the next pregnancy. ## Treatments: what the evidence shows - **Antiphospholipid syndrome:** low-dose aspirin with heparin (ESHRE suggests it for women with three or more losses; the RCOG advises offering it from a positive pregnancy test until at least 34 weeks, after discussing benefits and risks). - **Bleeding in a new pregnancy after previous losses:** vaginal progesterone may improve the chance of a live birth in women with three or more losses (ESHRE), and the RCOG advises considering a progestogen for women with recurrent miscarriage who bleed in early pregnancy. - **Thyroid:** an underactive thyroid (overt hypothyroidism) is treated; levothyroxine is not recommended for women with normal thyroid function who only have thyroid antibodies. - **Unexplained losses:** aspirin or heparin are not recommended, nor are steroids or lymphocyte immunisation; the evidence is insufficient for intralipids, and ESHRE's 2022 update found no evidence to recommend G-CSF. ESHRE suggests that repeated high doses of intravenous immunoglobulin very early in pregnancy may help women with four or more unexplained losses. The RCOG finds insufficient data to support routine PGT-A for unexplained recurrent miscarriage. - **A uterine septum:** the evidence on removing it by hysteroscopy is limited and mixed. ESHRE notes that one small trial showed no benefit, while the RCOG suggests considering it, ideally within audit or research. ## What is known about the outlook In many couples, no cause is found. The [ESHRE guideline](https://www.eshre.eu/Guidelines-and-Legal/Guidelines/Recurrent-pregnancy-loss) estimates that the known factors together account for about 50 to 60 percent of recurrent pregnancy loss, leaving 40 to 50 percent unexplained. It also notes that couples with recurrent loss have a good prognosis for a next live birth, especially when the woman is younger and the number of previous losses is lower, and it recommends basing the prognosis on her age and full pregnancy history. ESHRE states that there is no evidence that stress is a direct cause of pregnancy loss. For unexplained recurrent miscarriage, the [RCOG](https://www.rcog.org.uk/guidance/browse-all-guidance/green-top-guidelines/recurrent-miscarriage-green-top-guideline-no-17/) recommends supportive care, ideally in a dedicated recurrent miscarriage clinic. ## Questions worth asking your doctor - Which of the recommended tests have been done, and which are still worth doing? - Was the pregnancy tissue tested, and if not, is a karyotype of both partners advised? - Is any proposed treatment supported by the ESHRE or RCOG guidelines in my situation? - What early-pregnancy care and support would be available in a next pregnancy? ## Risks and limits Most of the investigation consists of blood tests and ultrasound. A hysteroscopy, when needed, is a minor procedure with small risks of infection or bleeding. Treatments such as heparin and aspirin can cause bruising or bleeding and are used only when a test shows a reason for them. ESHRE notes that most of its recommendations rest on low or very low quality evidence, so some may change as research continues. ## Common questions **Should we be investigated after two losses, or wait for three?** Guidelines differ. ESHRE defines recurrent loss from two losses and recommends some tests, such as antiphospholipid antibodies, after two; the RCOG uses three but encourages evaluation after two when an underlying cause is suspected. Your doctor can advise which tests are reasonable now. **Can a cause always be found?** No. In many couples all the tests are normal, and ESHRE estimates that close to half of recurrent pregnancy loss remains unexplained. Even then, the outlook for a next pregnancy is often good, particularly at younger ages and after fewer losses. **Does IVF with PGT-A prevent miscarriage?** The HFEA finds high-quality evidence that PGT-A reduces the chance of miscarriage, but rates it red for improving the chance of having a baby for most patients. The RCOG finds insufficient data to support its routine use for unexplained recurrent miscarriage, and PGT-A does not address other causes. **Is stress a cause of miscarriage?** ESHRE states that there is no evidence that stress is a direct cause of pregnancy loss. Stress and low mood are common after losses, and emotional support is part of good care. **Evidence basis:** This page is based on the ESHRE guideline on recurrent pregnancy loss (2022 update) and the RCOG Green-top Guideline No. 17 (2023); most of their recommendations rest on low-quality evidence, and the page says where evidence is limited. ## References 1. Guideline on the management of recurrent pregnancy loss, European Society of Human Reproduction and Embryology (ESHRE) (2023) — [eshre.eu](https://www.eshre.eu/Guidelines-and-Legal/Guidelines/Recurrent-pregnancy-loss) 2. ESHRE guideline: recurrent pregnancy loss: an update in 2022, Human Reproduction Open (ESHRE) (2023) — [doi:10.1093/hropen/hoad002](https://doi.org/10.1093/hropen/hoad002) 3. Recurrent Miscarriage (Green-top Guideline No. 17), Royal College of Obstetricians and Gynaecologists (RCOG) (2023) — [rcog.org.uk](https://www.rcog.org.uk/guidance/browse-all-guidance/green-top-guidelines/recurrent-miscarriage-green-top-guideline-no-17/) 4. Pre-implantation genetic testing for aneuploidy (PGT-A), Human Fertilisation and Embryology Authority (HFEA) (2023) — [hfea.gov.uk](https://www.hfea.gov.uk/treatments/treatment-add-ons/pre-implantation-genetic-testing-for-aneuploidy-pgt-a/) Written and reviewed by [Dr. Ghina Shami](https://www.ghinashami.com/en/about/), Consultant, Reproductive Medicine and Infertility · 13 October 2026 · [How these pages are prepared](https://www.ghinashami.com/en/legal/#accuracy)