Recurrent Pregnancy Loss

Introduction

If you are reading this, you have likely been through more than one pregnancy loss. That experience is painful in ways that words struggle to capture, and the grief is often layered with confusion: why is this happening, was anything missed, and what should happen next. This article is written for people who are now in the space between losses — trying to understand what recurrent pregnancy loss means, what can be tested for, and what choices may lie ahead.

Recurrent pregnancy loss, sometimes called recurrent miscarriage, is a recognised clinical situation with a structured approach to evaluation and care. While not every couple receives a clear answer, many do, and even when no specific cause is identified, the outlook for a future pregnancy is generally more hopeful than it may feel right now. The pages that follow describe what doctors look for, the tests that are usually offered, the treatment options that may apply, and the kind of support that can help during a next pregnancy.

What Is Recurrent Pregnancy Loss?

Recurrent pregnancy loss (RPL) is most commonly defined as the loss of two or more pregnancies. The European Society of Human Reproduction and Embryology (ESHRE) uses this two-or-more definition, including non-visualised pregnancy losses (such as biochemical pregnancies, where the pregnancy is confirmed only by a positive test). The American Society for Reproductive Medicine (ASRM) uses a similar threshold of two or more clinical pregnancy losses. Some older definitions and some health systems, including parts of the United Kingdom under Royal College of Obstetricians and Gynaecologists (RCOG) guidance, have historically used three or more losses as the trigger for full investigation, though current practice in many centres is to begin evaluation after two.

A few important distinctions:

• Pregnancy loss in this context usually means loss before 20 to 24 weeks of pregnancy — the cut-off varies between guidelines. Losses after this point are typically classified as stillbirth and investigated separately.
• Primary RPL refers to recurrent losses in someone who has never had a live birth.
• Secondary RPL refers to recurrent losses after one or more previous successful pregnancies.
• Early loss (before about 10 weeks) and late loss (after about 10–12 weeks) often have different underlying causes, which influences how the evaluation is approached.

Pregnancy loss in general is common — roughly one in four to one in five recognised pregnancies ends in miscarriage. Recurrent loss is less common, affecting around 1 to 2 percent of couples trying to have a child if the threshold is three losses, and up to about 5 percent if the threshold is two losses. The fact that single miscarriages are so common is part of why doctors often wait for a pattern before launching a full investigation: most single losses are random events that do not repeat.

Causes and Contributing Factors

Recurrent pregnancy loss is not one condition with one cause. It is an outcome that can arise from many different problems, and in a significant proportion of couples, no clear cause is found even after thorough testing. Major societies group the recognised causes into several broad categories.

Genetic and Chromosomal Causes

The most common single reason for any individual miscarriage is a chromosomal abnormality in the embryo — the pregnancy has the wrong number of chromosomes and cannot develop. These are usually random events. However, in a small percentage of couples with recurrent loss, one partner carries a balanced translocation, meaning their own chromosomes are rearranged but complete. The partner is healthy, but when eggs or sperm form, some carry an unbalanced version of the chromosomes, which can lead to repeated miscarriages.

For this reason, both partners may be offered a blood test called a karyotype, or a test on tissue from a recent miscarriage to see whether the embryo had a chromosomal abnormality. Results help doctors understand whether the losses are likely random or pointing to a treatable pattern.

Anatomical Causes (the Shape of the Uterus)

Sometimes the shape or structure of the uterus contributes to recurrent loss. Examples include:

• Septate uterus — a band of tissue divides the inside of the uterus, often present from birth. This is the uterine shape most consistently linked to recurrent loss, particularly second-trimester loss.
• Bicornuate, unicornuate, or other Müllerian anomalies — differences in how the uterus formed before birth.
• Fibroids that distort the inside of the uterine cavity (submucosal fibroids).
• Intrauterine adhesions (Asherman syndrome) — scar tissue inside the uterus, often after a previous procedure or infection.
• Cervical insufficiency — the cervix opens too early in pregnancy. This is a common cause of mid-trimester loss rather than early loss.

Hormonal and Metabolic Causes

Several hormonal conditions are associated with pregnancy loss:

• Uncontrolled thyroid disease, both underactive (hypothyroidism) and overactive (hyperthyroidism). The presence of thyroid antibodies, even with normal thyroid hormone levels, is also being studied for its role.
• Poorly controlled diabetes, particularly around the time of conception.
• Polycystic ovary syndrome (PCOS), which can be associated with insulin resistance and altered hormone levels.
• Obesity or significant underweight, both of which can affect ovulation and pregnancy outcome.

Whether a low level of the hormone progesterone is a cause of recurrent loss, or simply a sign of an already-failing pregnancy, has been debated. Progesterone supplementation is discussed later in this article.

Immune Causes

The clearest immune cause of recurrent pregnancy loss is antiphospholipid syndrome (APS). In APS, the body produces antibodies that increase the tendency for blood clots and interfere with the developing placenta. Diagnosis requires both specific blood test results and a clinical history that fits — the testing must be repeated, typically 12 weeks apart, to confirm.

Other immune theories — involving natural killer cells, cytokines, and various inflammatory markers — remain areas of active research. Major societies including ESHRE and ASRM currently advise against routine testing or treatment based on these markers outside of research settings, because the evidence does not yet support them as reliable guides to care.

Clotting (Thrombophilia) Causes

Inherited tendencies to form blood clots, called inherited thrombophilias (such as factor V Leiden, prothrombin gene mutation, or protein C and S deficiencies), have a complex relationship with pregnancy loss. The connection with late pregnancy loss is clearer than with early loss. Testing is generally reserved for people with a personal or family history suggesting thrombophilia, or with late-pregnancy losses.

Male-Partner Factors

Most evaluation has historically focused on the person carrying the pregnancy, but the male partner's contribution matters. Sperm DNA fragmentation — damage to the genetic material within sperm — is being studied as a possible contributor to recurrent loss. Advanced paternal age, smoking, obesity, and exposure to heat or toxins can affect sperm quality. Testing of sperm DNA fragmentation is offered in some centres, although guidelines vary on how routinely it should be used.

Lifestyle and Environmental Factors

Several modifiable factors are associated with higher rates of miscarriage:

• Smoking by either partner
• Heavy alcohol use
• High caffeine intake
• Recreational drug use
• Significant obesity or underweight
• Some occupational exposures (chemicals, certain medications, radiation)

Age

The age of the egg is one of the strongest single predictors of pregnancy loss. Miscarriage rates rise steeply from the late 30s onwards, primarily because the proportion of eggs with chromosomal abnormalities increases with age. Paternal age has a smaller but measurable effect.

When No Cause Is Found

In a substantial proportion of couples with recurrent loss — often quoted as around half — no specific cause is identified even after complete evaluation. This is called unexplained recurrent pregnancy loss. It can feel like the most difficult outcome of the workup. However, “unexplained” is not the same as “hopeless.” The chance of a successful next pregnancy with supportive care is generally still good, and this is discussed later in the article.

The Evaluation: What Tests Are Usually Done

The point of the evaluation is to identify any cause that can be treated, to understand the level of risk in a future pregnancy, and to guide what kind of monitoring and support will help. ESHRE and ASRM guidance describe a structured workup that most fertility and obstetric specialists follow, with some local variation.

History and Examination

Evaluation begins with a detailed history from both partners. This covers the timing and details of each loss, menstrual history, previous pregnancies, medical conditions, medications, family history, and lifestyle factors. Examination may include a pelvic exam. The history alone often shapes which tests are most useful.

Imaging of the Uterus

To assess the shape of the uterus and look for fibroids or adhesions, doctors commonly order:

• Transvaginal ultrasound — the standard first-line imaging.
• 3D ultrasound or saline infusion sonohysterography (where saline is injected into the uterus during ultrasound) for better detail.
• Hysteroscopy — a thin camera passed into the uterus, sometimes done as part of treatment if an abnormality is suspected.
• MRI in selected cases, particularly when uterine anomalies are complex.

Blood Tests

Standard blood tests in a recurrent loss workup often include:

• Antiphospholipid antibodies — lupus anticoagulant, anticardiolipin antibodies, and anti-beta-2-glycoprotein-I antibodies. Tested twice, at least 12 weeks apart.
• Thyroid function — TSH and free T4, sometimes with thyroid antibodies.
• HbA1c or fasting glucose if diabetes is a concern.
• Prolactin in some cases.
• Karyotype of both partners, particularly if there is a personal or family history that suggests a chromosomal issue, or after several losses.
• Thrombophilia screening in selected cases (typically late losses or relevant family history), not routinely.

Testing the Pregnancy Tissue

When a miscarriage occurs, testing the tissue (called products of conception) for chromosomal abnormalities can be informative. A normal chromosomal result on the tissue points towards a maternal or uterine cause and may prompt further investigation. An abnormal result usually indicates that the loss was due to a random chromosomal error, which is often reassuring for the future.

Tests Generally Not Recommended Routinely

Several tests are sometimes offered but are not supported by current major society guidance for routine use in recurrent loss:

• Natural killer (NK) cell testing
• Cytokine profiles
• HLA matching between partners
• Routine inherited thrombophilia panels in the absence of clinical indications
• Most “reproductive immunology” panels offered outside research settings

This does not mean these tests are never useful in any patient — only that current evidence does not support testing every couple. The presence of these tests on offer at some clinics, often with treatments attached, is a topic worth discussing openly with your treating doctor.

Treatment Based on Cause

When a cause is found, treatment is tailored to that cause. The following describes what major societies and current clinical practice suggest for the more commonly identified situations.

Genetic and Chromosomal Issues

If one partner carries a balanced translocation, options that may be discussed include:

• Natural conception with genetic counselling — many such couples do go on to have a healthy pregnancy without intervention; the counselling helps couples understand the risks.
• IVF with preimplantation genetic testing for structural rearrangements (PGT-SR) — embryos are tested before transfer to select those with a balanced or normal chromosome arrangement.
• IVF with preimplantation genetic testing for aneuploidy (PGT-A) — sometimes considered for couples with recurrent loss linked to embryonic chromosomal errors, particularly with advancing maternal age. Whether PGT-A improves live birth rates in recurrent loss specifically is still debated.
• Use of donor eggs or donor sperm in selected situations.

Uterine Shape and Cavity Issues

• Septate uterus — surgical removal of the septum (hysteroscopic septum resection) is often considered, particularly with a history of recurrent loss, although the evidence base is still developing.
• Submucosal fibroids that distort the cavity — usually removed by hysteroscopy.
• Intrauterine adhesions — hysteroscopic adhesiolysis (cutting the adhesions) and post-operative measures to prevent re-formation.
• Cervical insufficiency — in a future pregnancy, a cervical cerclage (a stitch to keep the cervix closed) and/or vaginal progesterone may be offered, depending on the history and findings.

Hormonal and Metabolic Conditions

• Thyroid disease — thyroid hormone levels are optimised before pregnancy and monitored carefully through pregnancy.
• Diabetes — tight blood sugar control before and during pregnancy reduces the risk of miscarriage and other complications.
• PCOS and insulin resistance — lifestyle changes and sometimes medication (such as metformin in specific situations) may be discussed.
• Prolactin elevation — treatment with medication if indicated.

Antiphospholipid Syndrome

For people with confirmed antiphospholipid syndrome and a history of recurrent loss, current guidance from ESHRE, ASRM, and RCOG describes low-dose aspirin combined with low-molecular-weight heparin, started after a pregnancy is confirmed, as the standard approach. This combination has been shown in clinical studies to improve live birth rates in this specific group. It is not recommended for couples who do not have APS.

Inherited Thrombophilia

For inherited thrombophilias, anticoagulant treatment is generally limited to people with specific clinical indications (such as a personal history of clots or certain late-pregnancy complications) rather than offered routinely for early recurrent loss. Current ESHRE guidance does not recommend heparin treatment for couples with inherited thrombophilia and unexplained early recurrent loss.

Lifestyle Modification

Even when a specific medical cause is found, lifestyle factors are addressed alongside treatment. Doctors commonly recommend:

• Stopping smoking, including second-hand smoke
• Stopping or significantly reducing alcohol
• Limiting caffeine
• Reaching a healthier body weight before pregnancy where possible
• Taking folic acid before conception
• Reviewing all current medications with a doctor before trying again

Progesterone

The role of progesterone in recurrent loss has been studied extensively. Current evidence, including the PROMISE and PRISM trials, suggests that vaginal progesterone may benefit women with a history of previous miscarriages who present with bleeding in early pregnancy. UK national guidance has incorporated this into practice. Whether progesterone benefits women with recurrent loss but no early bleeding is less clear. Whether and how to use progesterone is a clinical decision based on each person's history.

Unexplained Recurrent Pregnancy Loss

When no cause is identified, treatment focuses on supportive care in a future pregnancy. This is not the same as no care — it is care without a specific medical target. Key elements often include:

• Early pregnancy ultrasounds to confirm the pregnancy is developing and to provide reassurance.
• Frequent contact with a doctor or midwife, sometimes called “tender loving care” in the research literature. Studies suggest that close supportive follow-up in early pregnancy is associated with better outcomes in unexplained recurrent loss, although it is hard to study this in clinical trials.
• Lifestyle optimisation as above.
• Discussion of progesterone as one possible option.

Treatments commonly marketed for unexplained recurrent loss — including intravenous immunoglobulin, intralipid infusions, steroids, and various immune-modulating treatments — are not currently supported by ESHRE or ASRM guidance for routine use because the evidence does not show consistent benefit and there are real risks. These treatments may still be offered in some settings; discussing the evidence base openly with your specialist is important.

The Next Pregnancy: What Care Often Looks Like

Once a couple is ready to try again, care in a subsequent pregnancy is usually more closely supervised than a standard pregnancy. The exact pattern depends on what was found in the evaluation, but common features include:

• Pre-pregnancy review to confirm any chronic conditions are optimised and any medications are appropriate.
• Early confirmation of pregnancy, often with blood tests for hCG levels.
• Early ultrasound, typically around 6–8 weeks, to confirm the pregnancy is in the uterus and the heartbeat is present, and sometimes repeated at intervals.
• Specific medications based on the diagnosis — for example, aspirin and heparin for APS, thyroid medication adjustments, or progesterone in selected cases.
• Closer follow-up, both medical and emotional, particularly through the gestational age at which previous losses occurred.
• Cervical monitoring or cerclage if there is a history pointing to cervical insufficiency.
• Standard pregnancy screening — first-trimester screening, anatomy scan, and gestational diabetes testing — carried out as for any pregnancy.

One challenge that is rarely written down but commonly felt is that each milestone of the next pregnancy — the positive test, each ultrasound, the moment of passing the gestational age of a previous loss — can carry a unique mixture of hope and fear. Many people find that the anxiety does not lift on a particular date but eases gradually over weeks.

Recurrent pregnancy loss is a medical situation, but the experience of it is much more than medical. Grief after miscarriage is often underestimated by people who have not been through it. After repeated losses, grief can compound — not just for the pregnancies lost, but for the future that was being imagined.

Common experiences include:

• Feeling isolated, especially as friends and family may run out of words after the first loss.
• Anxiety about a future pregnancy, including avoidance of pregnancy or, conversely, urgency to try again immediately.
• Differences between partners in how grief is expressed, including different timelines for being ready to try again.
• Difficult feelings around other people's pregnancies and births.
• Anniversaries of losses or expected due dates carrying unexpected weight.

Mental health support is not a sign that something has gone wrong — it is a recognised part of care for recurrent loss. This can include counselling, peer support groups, and, in some cases, medication for depression or anxiety. ESHRE guidance specifically mentions that psychological support should be offered to couples with recurrent pregnancy loss.

For couples, talking openly about what each person needs — whether that is conversation, quiet, time, or trying again — can prevent grief from creating distance. There is no single right way through this.

How Likely Is a Successful Next Pregnancy?

This is one of the most important questions for couples in this situation, and one of the hardest to answer precisely because the chance depends on so many factors — age, number of previous losses, whether a cause was found, and what treatments are appropriate. However, the general picture from clinical experience and research is more hopeful than couples often expect:

• The majority of couples with recurrent pregnancy loss do go on to have a successful pregnancy, often without needing IVF or assisted reproduction.
• Even with several previous losses and no identified cause, the chance of a successful next pregnancy with supportive care is generally good for most couples.
• Age is the strongest single factor that affects this, with chances declining steeply through the late 30s and 40s.
• Identifying and treating a specific cause — such as antiphospholipid syndrome, thyroid disease, or a uterine septum — improves the outlook further for that group.

Personalised estimates are best discussed with your specialist, who can take account of your specific history and findings. Numbers offered from large studies are averages and may not capture your situation accurately.

When to Seek Urgent Care

During any pregnancy after recurrent loss, certain symptoms should prompt immediate medical attention:

• Heavy vaginal bleeding (soaking pads)
• Severe abdominal or pelvic pain
• Shoulder-tip pain, dizziness, or fainting (which can suggest ectopic pregnancy)
• Fever with bleeding or discharge
• Sudden loss of pregnancy symptoms accompanied by other warning signs

Lighter spotting or mild cramping is common in early pregnancy and is not always a sign of loss, but with a history of recurrent loss, doctors will usually want to assess you promptly when in doubt.

Frequently Asked Questions

How many miscarriages before we should be investigated?

Current ESHRE and ASRM guidance suggests evaluation after two losses, particularly for people over 35 or where there is concern about a specific cause. Some health systems use three losses as the threshold. If you have had two losses and want to begin evaluation, this is a reasonable request to discuss with your doctor.

Does having recurrent miscarriages mean I will not be able to have a child?

For most couples, no. Most people with recurrent pregnancy loss do go on to have a successful pregnancy. The path to that pregnancy may involve treatment, closer monitoring, or simply time and supportive care, but recurrent loss is not the same as infertility, and many couples have already shown they can conceive.

Was the miscarriage something I did?

Almost never. Most miscarriages are not caused by anything the parent did or did not do. Working, exercising at a normal level, having intercourse, travelling, stress, lifting routine objects — none of these cause miscarriage. The factors that do increase risk — smoking, heavy alcohol use, uncontrolled chronic conditions, advanced age — are addressed during the workup. Guilt is a common feeling but is rarely supported by the evidence.

How long should we wait before trying again?

From a purely medical standpoint, most doctors are comfortable with couples trying again after one or two normal menstrual cycles following an uncomplicated early miscarriage. Some research even suggests that conceiving sooner does not worsen outcomes. The more important question is often emotional readiness, which varies. There is no “correct” waiting time.

Will IVF help us avoid another miscarriage?

IVF on its own does not prevent miscarriage for most couples with recurrent loss. IVF combined with preimplantation genetic testing can be helpful in specific situations — such as a known parental chromosomal rearrangement — and is sometimes considered for women with advanced age and recurrent loss. Whether IVF with PGT-A improves live birth rates in unexplained recurrent loss is still debated. This is a decision best made with a fertility specialist who knows your situation.

Should we both be tested?

Yes, in most cases. While more of the investigation focuses on the person carrying the pregnancy, the male partner's history, karyotype (in selected cases), and sometimes sperm assessment are part of a complete evaluation.

If no cause is found, is there any point in continuing?

Yes. Unexplained recurrent loss does not mean a hopeless next pregnancy. The majority of couples with unexplained recurrent loss go on to have a successful pregnancy with supportive care. “Unexplained” means that current tests cannot identify a specific medical cause — it does not predict the future.

Are there any vitamins or supplements that help?

Folic acid before and during early pregnancy is standard. Vitamin D is often checked and supplemented if low. Beyond these, the evidence for specific supplements in recurrent loss is limited. Any supplement should be discussed with your doctor, because some can interact with medications or are not advised in pregnancy.

Can stress cause a miscarriage?

Ordinary life stress does not cause miscarriage. This is one of the more important things to hear when grief is heavy, because the temptation to find a reason can land on something the person could have controlled. There is no good evidence that workplace stress, relationship stress, or worry in itself causes a pregnancy to be lost.

What if I have a partner with a balanced translocation? Will all our pregnancies be lost?

No. Many couples in this situation do have healthy pregnancies through natural conception. Genetic counselling helps couples understand the specific pattern in their case and the options, which may include continuing to try naturally or considering IVF with genetic testing of embryos.

Conclusion

Recurrent pregnancy loss is a painful and disorientating experience, but it is also a recognised clinical situation with a structured way to investigate and care for couples who go through it. Some causes are found and treated. Others are not found, and treatment focuses on supportive care in the next pregnancy. In both situations, most couples do go on to have a successful pregnancy.

What helps, more often than not, is a careful evaluation by a specialist with experience in recurrent loss; honest conversation about what the evidence does and does not support; addressing lifestyle factors where they apply; treating any specific medical cause that is found; and bringing emotional support into the picture alongside the medical care. The next pregnancy after recurrent loss is rarely an easy one emotionally, but with the right combination of care, the outlook for most couples is better than they expect when they begin.