Among all the experiences that can accompany the journey toward parenthood, recurrent miscarriage carries a particular and compounding grief. Each loss is its own bereavement — a pregnancy that was hoped for, a future that was beginning to be imagined, and then gone. And when the loss happens again, and again, the grief multiplies but also transforms into something else: the desperate, legitimate need for an explanation.
Why does this keep happening? What is wrong? Is there something that can be done?
Recurrent miscarriage — defined clinically as two or more consecutive pregnancy losses before 24 weeks of gestation — affects approximately 1 to 2 percent of couples trying to conceive. The experience is both medically complex and profoundly human. And the clinical response it deserves — a thorough, compassionate, specific investigation — is, in many clinical settings, not what couples receive.
This article addresses what recurrent miscarriage is, what causes it, what the investigation should include, how fertility treatment — particularly IVF with PGT-A testing — is connected to its management, and what realistic expectations for subsequent pregnancy look like after appropriate investigation and treatment.
What Is Recurrent Miscarriage?
Recurrent miscarriage — also called recurrent pregnancy loss (RPL) — is defined by most clinical guidelines as two or more pregnancy losses before 24 weeks of gestation. Some guidelines define it as three or more losses, but the current clinical consensus increasingly supports investigation after two consecutive losses — recognising that waiting for a third loss before investigating causes both clinical harm (additional preventable losses) and emotional harm (additional grief that a timely diagnosis might have prevented).
Miscarriage is more common than most people realise — approximately 15 to 20 percent of all recognised pregnancies end in miscarriage, the majority in the first trimester. Most miscarriages are isolated events — caused by chromosomal abnormalities in the embryo that arise spontaneously and are not associated with any ongoing condition in either partner. The probability of having one miscarriage and then going on to have a successful pregnancy is high.
Recurrent miscarriage is different. When miscarriage happens two or more times consecutively, the probability that each loss is a random, isolated event decreases significantly. The statistical probability of three consecutive miscarriages occurring by chance alone — assuming a 15 to 20 percent single-event rate — is approximately 0.3 to 0.4 percent. This low probability means that couples with recurrent miscarriage have a meaningful prior probability of having an underlying, identifiable cause — and that cause deserves to be found.
The Causes of Recurrent Miscarriage
The causes of recurrent miscarriage are multiple, and identifying which cause — or which combination of causes — is responsible for a specific couple's losses is the purpose of the investigation.
Embryonic Chromosomal Abnormality — the Most Common Cause
Chromosomal abnormality in the embryo — aneuploidy, meaning an incorrect number of chromosomes — is the single most common cause of both isolated and recurrent miscarriage. Aneuploid embryos implant but cannot develop normally, and the pregnancy ends, typically in the first trimester.
In younger women, aneuploid embryos arise from errors in egg maturation — a random event that can occur in any cycle. In older women — over 35, and increasingly so over 38 — the proportion of eggs carrying chromosomal abnormalities rises substantially with age, and the increased miscarriage rate with advancing maternal age is primarily driven by this rising aneuploidy rate.
For couples with recurrent miscarriage, the contribution of embryonic chromosomal abnormality can be assessed through PGT-A (preimplantation genetic testing for aneuploidies) in an IVF cycle — testing embryos before transfer to identify those with the correct number of chromosomes and selecting only euploid (chromosomally normal) embryos for transfer. This approach directly addresses the most common cause of recurrent miscarriage.
Uterine Structural Abnormalities
Structural abnormalities of the uterine cavity — both congenital and acquired — are present in a proportion of women with recurrent miscarriage and are among the most important treatable causes.
Uterine septum — a congenital band of fibrous tissue dividing the uterine cavity, arising from incomplete fusion of the Müllerian ducts during fetal development — is the most common congenital uterine abnormality associated with recurrent miscarriage. A septum provides a poor vascular environment for placental implantation — placentation on the avascular septal tissue cannot sustain a developing pregnancy adequately. Hysteroscopic metroplasty — surgical division of the septum through the hysteroscope — is a well-established treatment with evidence supporting reduced miscarriage rates after repair.
Intrauterine adhesions (Asherman syndrome) — bands of scar tissue within the uterine cavity — can prevent adequate endometrial development and disrupt early placental blood supply. They typically develop after uterine surgery, curettage, or infection.
Submucosal fibroids and endometrial polyps — as discussed in our conditions articles — can disrupt implantation and early pregnancy development, contributing to recurrent loss in some women.
Congenital uterine anomalies — including bicornuate uterus and arcuate uterus — are associated with recurrent miscarriage in varying degrees. Bicornuate uterus — in which the uterus has two horns — is associated with second-trimester loss due to cervical incompetence and abnormal uterine shape more than first-trimester loss. The clinical significance of arcuate uterus — a mild midline indentation of the uterine fundus — for recurrent miscarriage is debated.
Antiphospholipid Syndrome — the Most Important Treatable Systemic Cause
Antiphospholipid syndrome (APS) — an autoimmune condition in which antibodies against phospholipids and phospholipid-binding proteins cause abnormal clotting and impair placental blood flow — is present in approximately 15 percent of women with recurrent miscarriage. It is the most important treatable systemic cause of recurrent pregnancy loss.
APS is diagnosed through positive testing for antiphospholipid antibodies — anticardiolipin antibodies, anti-beta-2 glycoprotein I antibodies, and lupus anticoagulant — on two occasions at least twelve weeks apart. The diagnostic requirement for two positive tests at twelve-week intervals is important — a single positive test may be transient and not represent true APS.
The treatment for APS in pregnancy — low-dose aspirin (typically 75 to 150 mg daily, started before conception or early in pregnancy) combined with low-molecular-weight heparin (a blood-thinning injection given daily through the pregnancy) — reduces the abnormal clotting that APS causes at the placental interface and significantly improves pregnancy outcomes. Multiple randomised trials have demonstrated that aspirin and heparin combination therapy reduces miscarriage rates in APS from approximately 90 percent to approximately 25 to 30 percent in women with three or more previous losses.
APS is the most compelling argument for the importance of the recurrent miscarriage investigation — because it is a specific, diagnosable condition that has a specific, effective treatment that dramatically changes outcomes when applied. Every couple with recurrent miscarriage who has not been tested for antiphospholipid antibodies has had an incomplete investigation.
Thrombophilias — Inherited Clotting Disorders
Inherited thrombophilias — genetic conditions that increase the tendency of blood to clot — include Factor V Leiden mutation, prothrombin gene mutation, protein C deficiency, protein S deficiency, and antithrombin III deficiency. These conditions can impair placental blood flow through the same mechanism as APS — abnormal clotting in the small blood vessels of the developing placenta.
The evidence for a causal role of inherited thrombophilias in recurrent miscarriage is less consistent than for APS, and the evidence that anticoagulation treatment in thrombophilic women improves pregnancy outcomes is also less definitive. Current guidelines therefore recommend selective rather than universal thrombophilia screening in recurrent miscarriage — typically in women with a personal or family history of thromboembolic events, or in women whose other investigations have not revealed an explanation.
Chromosomal Abnormalities in the Parents
A structural chromosomal abnormality in one or both partners — most commonly a balanced reciprocal translocation or a Robertsonian translocation — can produce aneuploid embryos at a higher-than-chance rate, causing recurrent miscarriage.
Balanced translocations are present in approximately 3 to 5 percent of couples with recurrent miscarriage. A parent carrying a balanced translocation has the correct total amount of genetic material — rearranged between chromosomes but balanced — and is typically healthy. But when their gametes form, the rearranged chromosomes may be distributed unequally, producing embryos with too much or too little genetic material — unbalanced translocations that cannot develop normally.
Parental karyotyping — a blood test to examine the chromosomes of each partner — is a standard component of the recurrent miscarriage investigation. If a balanced translocation is found in either partner, the clinical management changes significantly — specifically, PGT-A or PGT-SR (structural rearrangement testing) in an IVF cycle becomes the primary strategy, identifying unaffected embryos for transfer.
Hormonal and Metabolic Factors
Thyroid dysfunction — particularly hypothyroidism — is associated with increased miscarriage rates. Thyroid antibodies (anti-TPO and anti-thyroglobulin) are associated with elevated miscarriage risk even in women with normal TSH levels, possibly through direct effects on the endometrial environment. Thyroid assessment — TSH and thyroid antibodies — is a standard component of the recurrent miscarriage investigation.
Poorly controlled diabetes mellitus is associated with elevated miscarriage rates. Women with PCOS have an elevated miscarriage risk — related to elevated LH at the time of fertilization, insulin resistance effects on the endometrial environment, and potentially elevated androgens.
Luteal phase deficiency — inadequate progesterone production after ovulation — has been proposed as a cause of recurrent miscarriage, but the evidence is mixed. Progesterone supplementation in early pregnancy for women with recurrent miscarriage has been evaluated in trials, and the PRISM trial demonstrated a modest but statistically significant improvement in live birth rates in women with previous recurrent miscarriage who received vaginal progesterone in early pregnancy.
Unexplained Recurrent Miscarriage
Despite thorough investigation, a proportion of couples with recurrent miscarriage — approximately 50 to 60 percent — have no identifiable cause found. This proportion may decrease as investigation techniques improve — particularly as sperm DNA fragmentation testing, comprehensive chromosomal analysis of miscarriage tissue, and novel immunological markers are incorporated into standard investigation protocols.
For couples with unexplained recurrent miscarriage, the prognosis is not as bleak as the absence of a diagnosis might suggest. Studies of untreated couples with unexplained recurrent miscarriage who attempt subsequent pregnancy show live birth rates of approximately 65 to 75 percent — reflecting the fact that many unexplained recurrent miscarriage cases represent random chromosomal events that resolve over time rather than fixed ongoing pathology.
Supportive care — close early pregnancy monitoring, emotional support, and in some evidence bases the tender loving care effect itself — has been associated with improved outcomes in unexplained recurrent miscarriage, though the mechanism is not fully understood.
The Investigation That Every Couple With Recurrent Miscarriage Deserves
The complete recurrent miscarriage investigation should include the following.
Antiphospholipid antibody testing — anticardiolipin antibodies (IgG and IgM), anti-beta-2 glycoprotein I antibodies (IgG and IgM), and lupus anticoagulant — repeated at twelve-week intervals to confirm a positive result.
Parental karyotyping — chromosomal analysis of both partners' blood to identify balanced translocations or other structural chromosomal rearrangements.
Uterine cavity assessment — hysteroscopy is the gold standard, providing direct visualization of the cavity and identification of septum, adhesions, polyps, or fibroids that may be contributing to the losses.
Thyroid function and thyroid antibodies — TSH and anti-TPO antibodies.
Assessment of glycaemic control — fasting glucose and HbA1c where diabetes or significant PCOS is clinically suspected.
Chromosomal analysis of miscarriage tissue — where miscarriage tissue has been retained and is available, chromosomal analysis (array CGH or karyotyping) identifies whether the loss was aneuploid, providing the most direct evidence about cause. This analysis should be performed on future losses in couples with unexplained recurrent miscarriage, to build the evidence base for whether embryonic aneuploidy is the dominant mechanism.
Sperm DNA fragmentation testing — increasingly recognized as a contributing factor in recurrent pregnancy loss. Sperm with high DNA fragmentation may fertilize eggs but produce embryos with impaired developmental competence or chromosomal instability that leads to miscarriage. This test is not yet in all standard recurrent miscarriage guidelines but is performed at Metro IVF as a routine component of every male evaluation.
How IVF and PGT-A Are Connected to Recurrent Miscarriage Management
For couples with recurrent miscarriage where embryonic chromosomal abnormality is the primary identified or suspected cause — including older women, couples with parental chromosomal translocations, and couples with unexplained recurrent miscarriage who have had multiple losses — IVF with PGT-A testing offers the most direct approach to reducing the recurrence risk.
PGT-A tests each embryo produced in an IVF cycle for chromosomal number before transfer. Only euploid embryos — those with the correct complement of chromosomes — are transferred. Aneuploid embryos, which would otherwise result in a failed implantation or a miscarriage, are identified and not used.
The clinical rationale for PGT-A in recurrent miscarriage is compelling: by selecting only chromosomally normal embryos for transfer, the most common cause of both implantation failure and first-trimester miscarriage is directly addressed. The pregnancy that results from a euploid embryo transfer has a significantly higher probability of progressing to term than a pregnancy established from an untested embryo in a couple with a history of recurrent chromosomal losses.
PGT-A is not appropriate for every couple with recurrent miscarriage — particularly those where the losses have been shown to be euploid on testing of miscarriage tissue, or those with a specific treatable systemic cause such as APS. But for couples where chromosomal factors are likely — older women, translocation carriers, or couples with multiple losses after other causes have been addressed — it is a clinically rational and evidence-supported addition to the management strategy.
After the Investigation: What Improved Outcomes Look Like
For couples who receive a specific diagnosis from the recurrent miscarriage investigation, the prognosis with appropriate treatment is significantly better than without it.
Couples with APS treated with aspirin and heparin have live birth rates of approximately 70 to 75 percent in subsequent pregnancies — compared to approximately 10 percent without treatment.
Couples with uterine septum who undergo hysteroscopic repair have substantially reduced miscarriage rates in subsequent pregnancies — though the evidence from randomised trials is less conclusive than for APS treatment.
Couples with balanced translocations who use IVF and PGT-SR — selecting unaffected embryos — have substantially improved live birth rates per transfer compared to natural conception attempts.
Couples with thyroid autoimmunity who receive thyroid optimization and close monitoring in early pregnancy have modest but meaningful improvements in live birth rates.
And couples with unexplained recurrent miscarriage who are supported through close early pregnancy monitoring — with frequent reassurance ultrasounds, progesterone supplementation, and emotional support — have live birth rates in subsequent pregnancies that exceed what a history of multiple losses might initially suggest.
Your Next Step
If you have experienced two or more consecutive miscarriages and have not received a thorough investigation — or if you have had investigations that did not include antiphospholipid antibody testing, parental karyotyping, hysteroscopy, or sperm DNA fragmentation testing — a consultation with Dr. Ashish Soni at Metro IVF in Ambikapur provides the most complete recurrent miscarriage assessment available in the region.
The losses you have experienced deserve a thorough answer. And in many cases, that answer — specific, evidence-based, and actionable — changes the outcome of the next pregnancy.
Metro IVF Test Tube Baby Center Ambikapur, Chhattisgarh metrofertility.in Led by Dr. Ashish Soni — North India's First Fertility Super Specialist
Recurrent miscarriage has identifiable causes in many cases — and treatable ones. Book your consultation with Dr. Ashish Soni at Metro IVF today.