Recurrent miscarriage.

This film was made from interviews held with parents who have gone through recurrent miscarriage as part of The Baby Loss Series.

Recurrent miscarriage is defined as having 3 or more early (first trimester) miscarriages. Miscarriage can be devastating and having multiple miscarriages is often a very traumatic experience. 

There is no right or wrong way to feel after repeated losses but you and your partner (if you have one) may be struggling with grief, anxiety, and loss of hope. We hope the information on this page helps you both.

On this page 

What is recurrent miscarriage?

Causes of recurrent miscarriage 

Unexplained recurrent miscarriage

Tommy’s research into the causes of miscarriage

Tests and treatments for recurrent miscarriage

Pregnancy after recurrent miscarriage

Support for you

 

What is recurrent miscarriage?

Recurrent miscarriage is when you experience 3 or more early miscarriages (even if you have successful pregnancies in between). An early miscarriage is usually defined as one that happens in the first 12 weeks of pregnancy (also called the first trimester). The pregnancies do not have be all with the same partner. This definition is the one used in the UK. 

Recurrent miscarriage used to be defined as 3 miscarriages in a row. 

If you have experienced recurrent miscarriage, you can get tests on the NHS to try and find out why. 

In some other cases you may be able to get tests even if you have not had 3 early miscarriages. Our information on tests and treatments after miscarriage explains more.  

 

Causes of recurrent miscarriage

 

In this section we have listed things that could be the reason for all 3 (or more) of your losses. Some of these can be tested for and treated. We explain more about tests and treatments for recurrent miscarriage later on this page.

Abnormal chromosomes

Chromosomes are blocks of DNA that contain instructions for your baby’s development. The most common cause of recurrent miscarriage is that your baby has developed with the wrong number of chromosomes (too many or not enough). Occasionally the structure of the chromosome itself develops in the wrong way.  Most of the time this happens even though the parents themselves have normal chromosomes. In a small number of cases, one or both partners may repeatedly pass on an abnormal chromosome, causing recurrent miscarriage.  

Blood clotting disorders

Some blood clotting disorders, such as systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) may cause recurrent miscarriage. They cause ‘sticky blood’, which affects the flow of blood to the placenta and may cause clots in the placenta. If the placenta does not work properly, oxygen and nutrients can’t reach your baby. This may lead to miscarriage.  

All women and birthing people who experience recurrent miscarriage should be offered tests for these disorders (called ‘screening for antiphospholipid antibodies’). Treatment may involve thinning the blood with aspirin and heparin therapy.

Hormonal imbalances

Having too many or not enough of certain hormones in your body may make recurrent miscarriage more likely.

Problems with the thyroid have been linked to miscarriage and other pregnancy complications. Your thyroid is a gland in your neck that produces hormones. Well-controlled thyroid disease does not cause miscarriage. However, high levels of the ‘thyroid stimulating hormone’ (TSH) or the presence of thyroid antibodies, may put you at higher risk of miscarriage.

Diabetes. If you have diabetes and it is not properly managed, then you may have a higher chance of recurrent miscarriage. Diabetes will not increase your chance of miscarriage if you manage it in the ways recommended by your doctor. We have more information on diabetes and pregnancy here.

Prolactin is a hormone that is produced in your pituitary gland. It controls lots of bodily functions, including milk production6. If you have too much or too little prolactin, you may be at increased chance of miscarriage.

 

Polycystic ovarian syndrome (PCOS)

You have a slightly increased risk of recurrent of miscarriage if you have polycystic ovarian syndrome (PCOS). We don’t yet know exactly why. More research is needed.

 

The balance of cells in your womb lining

Tommy's research suggests that the balance of cells in your womb lining may play a part in infertility and miscarriage. They are developing ways of testing this balance. Some fertility clinics already offer tests to measure your level of uNK cells (one type of cell that is involved in this balance). However these tests do not give the full picture and are no longer recommended. 

 

The shape of your womb (uterine problems)

 An unusually shaped womb may increase your risk of recurrent miscarriage and premature birth. There are a number of ways to investigate the shape of the womb and depending on the findings, surgery may be recommended.

 

Cervical weakness

Your cervix is a ring of muscle at the base of your womb (uterus) that connects it to your vagina.  During labour it shortens and opens to allow the baby to pass through and be born. Sometimes it shortens and opens before it should (in the second or third trimester). This is called cervical weakness (sometimes called cervical incompetence or cervical insufficiency) and can cause second trimester loss (late miscarriage).

If you have a history of second trimester loss and doctors think you are at risk of cervical incompetence or cervical weakness, you may be offered a scan to assess the length of your cervix. They may recommend that you have a cervical cerclage (cervical stitch) either before or during a pregnancy.

 

Unexplained recurrent miscarriage

There may be no obvious cause of your recurrent miscarriages. Each loss might have been caused by something different. Sadly, tests may not always be able to work out exactly what happened in each case.

It can be difficult to be told that your recurrent miscarriages are unexplained, especially if that means there is nothing you can treat or change next time. It might help to know that most women who have had 3 unexplained miscarriages do go on to have a healthy pregnancy.  

You can read more about causes and risk factors of all types of miscarriage here. In some cases, you might be able to make changes to reduce your risk of miscarriage in the future.

Find out your chance of a successful pregnancy after miscarriage with our research-based Miscarriage Support Tool.

 

Tommy’s research into the causes of miscarriage

Most parents never find out why their miscarriage happened. We believe that you deserve to be told why your baby died in pregnancy. As well as ending the cycle of self-blame and guilt, this will improve our understanding of the biological processes at work. This can help us find ways to prevent miscarriages not caused by chromosomal abnormalities. This animation shows how we are finding the causes of miscarriage.

 

Tests and treatments for recurrent miscarriage

You should be offered tests at a specialist recurrent miscarriage centre after 3 early miscarriages.  Read more about the tests and treatments you should be offered after 3 miscarriages here.

If your doctor thinks your miscarriages might have an underlying cause, you may be offered tests after 2 early miscarriages.

If you have 1 second trimester loss (late miscarriage), you should be offered tests and investigations straight away. You can read more about second trimester loss here.

You may not be referred to a miscarriage specialist after 2 or 3 miscarriages that include ectopic or molar pregnancies.  For example, if you’ve had 1 ectopic pregnancy and 2 unexplained miscarriages, you may not be accepted for specialist miscarriage care in some areas.

This can be upsetting. But it is because we know what causes ectopic pregnancy or molar pregnancy, so further tests are not medically necessary.

Different areas have different rules. It’s worth talking to your GP about getting referred for specialist care if you have experienced other types of pregnancy loss.

 

Pregnancy after recurrent miscarriage

 

When should I start trying again?

Tests and investigations usually take time to arrange, and it takes more time to get the results.  

It’s your decision whether you continue to try for a pregnancy while you wait for the results.  

Some people want to try again quickly, others feel they need some time to prepare themselves emotionally and physically for a new pregnancy. There’s no right or wrong way to approach it. Read more about getting pregnant after miscarriage here.

 

Being pregnant after recurrent miscarriage

Pregnancy after miscarriage can be a very anxious time. It may be even harder after recurrent losses. If you have had 3 or more miscarriages, you should have specialist care, which can include extra scans. This will either be arranged by the hospital that has cared for you during your miscarriages, or through your GP. Our information on your care after 3 miscarriages includes more information on your care in future pregnancies too.

Once you are pregnant, if you have bleeding in early pregnancy (before 12 weeks), you should be treated with progesterone. Contact your nearest Early Pregnancy Assessment Unit (EPAU). Tell them you have miscarried before.

The EPU should be able to prescribe progesterone for you if you are bleeding in early pregnancy and have had one or more previous miscarriages. Before they prescribe it, they will need to check that your pregnancy is in the womb. This will be done with an ultrasound scan. This is to make sure that the pregnancy is not ectopic (in the fallopian tube or another place where it cannot develop).

If you have had 1 or 2 miscarriages and have bleeding in a following early pregnancy, taking progesterone in early pregnancy may increase your chances of having a successful pregnancy by roughly 5%.

If you have had 3 or more miscarriages and have bleeding in a following early pregnancy, taking progesterone in early pregnancy may increase your chances of having a successful pregnancy by roughly 15%. 

Read more about progesterone in early pregnancy here.

 

Support for you

You do not need to go through this alone. There are lots of organisations that can provide more advice and support.

If you’re worried that you or your partner are struggling to cope after losing a baby, please talk to your GP. They will be able to help you get the support you need. You might also find it helpful to look at our section on support after a miscarriage.

You can also talk to a Tommy’s midwife for free. You can call them Monday-Friday, 9am-5pm on 0800 0147 800 or you can email them at [email protected]. Our midwives are trained in bereavement support so will be able to talk to you about what you’re going through.

 

RCOG (2023) Recurrent miscarriage. Available at https://www.rcog.org.uk/for-the-public/browse-our-patient-information/recurrent-miscarriage/ (Accessed 23 January 2024) (Page last reviewed 06/2023)

NHS (2022) Miscarriage. Available at https://www.nhs.uk/conditions/miscarriage/ (Accessed 25 January 2024) (Page last reviewed: 9 March 2022 Next review due: 9 March 2025)

RCOG (2023) Recurrent miscarriage (Green-top Guideline No. 17). Available at https://www.rcog.org.uk/guidance/browse-all-guidance/green-top-guidelines/recurrent-miscarriage-green-top-guideline-no-17/ (Accessed 23 January 2024) (Page last reviewed 19/06/2023)

British Thyroid Association (nd) Your thyroid gland. Available at https://www.btf-thyroid.org/what-is-thyroid-disorder (Page accessed 24 January 2024)

The Society for Endocrinology (2023) You and your hormones - Prolactin. Available at: https://www.yourhormones.info/hormones/prolactin/ (Accessed 24 January 2024) (Page last reviewed 02/2023)

Cocksedge, KA. et al. (2008) ;A reappraisal of the role of polycystic ovary syndrome in recurrent miscarriage’. Reproductive BioMedicine Online, Volume 17, Issue 1, 2008, Pages 151-160, https://doi.org/10.1016/S1472-6483(10)60304-5.,

Brighton, P. et al (2017). ‘Clearance of senescent decidual cells by uterine natural killer cells in cycling human endometrium.’ eLife, 6, e31274. https://doi.org/10.7554/eLife.31274    

Díaz-Hernández I, Alecsandru D, García-Velasco JA, Domínguez F. Uterine natural killer cells: from foe to friend in reproduction. Hum Reprod Update. 2021 Jun 22;27(4):720-746. doi: 10.1093/humupd/dmaa062. PMID: 33528013.

ESHRE Working Group on Recurrent Implantation Failure, D Cimadomo, M J de los Santos, G Griesinger, G Lainas, N Le Clef, D J McLernon, D Montjean, B Toth, N Vermeulen, N Macklon, ESHRE good practice recommendations on recurrent implantation failure, Human Reproduction Open, Volume 2023, Issue 3, 2023, hoad023, https://doi.org/10.1093/hropen/hoad023

NICE (2023) Ectopic pregnancy and miscarriage: diagnosis and initial management. Available at https://www.nice.org.uk/guidance/ng126/chapter/Recommendations#early-pregnancy-assessment-services (Accessed 23 January 2024) (Page last reviewed 23/09/2023)

Coomarasamy, A. et al. (2019) ’A Randomized Trial of Progesterone in Women with Bleeding in Early Pregnancy’. The New England journal of medicine, 380(19), 1815–1824. https://doi.org/10.105/NEJMoa1813730

Review dates
Reviewed: 22 February 2024
Next review: 22 February 2027