About 50% of RPL cases can be explained and many treated effectively — particularly antiphospholipid syndrome (aspirin + heparin therapy achieves ~74% live birth rates). For the other 50% that remain unexplained, the outlook is still encouraging: 60–75% of women with unexplained RPL will have a successful pregnancy with supportive care alone. Getting a thorough workup matters, but so does knowing that the odds are genuinely in your favor.
What Is Recurrent Pregnancy Loss?
Recurrent pregnancy loss (RPL) — also called recurrent miscarriage — is defined as two or more pregnancy losses before 20 weeks gestation. ASRM recommends beginning evaluation after two consecutive losses, while some guidelines (ESHRE, RCOG) historically used three as the threshold.
The numbers put RPL in perspective: about 12–15% of clinically recognized pregnancies end in miscarriage. Approximately 5% of women will experience two losses, and roughly 1% will have three or more. While sporadic miscarriage is common and usually random, recurrent losses suggest an underlying factor worth investigating.
Miscarriage Risk by Age
| Age | Miscarriage Rate |
|---|---|
| 20–24 | ~11% |
| 25–29 | ~12% |
| 30–34 | ~15% |
| 35–39 | ~25% |
| 40–44 | ~51% |
| 45+ | ~93% |
Age is the single most significant independent risk factor for both sporadic and recurrent pregnancy loss, driven primarily by the rising rate of chromosomal abnormalities in eggs as women age.
What Causes Recurrent Pregnancy Loss?
RPL causes fall into several categories. A comprehensive workup can identify a cause in roughly 50% of cases — the other half remain unexplained.
Chromosomal Abnormalities
The most common cause of any single miscarriage. The embryo has too many or too few chromosomes (aneuploidy) and cannot develop normally. This is largely driven by egg quality and increases sharply with maternal age. Parental chromosomal translocations (structural rearrangements carried by one parent) account for 2–5% of RPL cases and can be identified through karyotyping.
Antiphospholipid Syndrome (APS)
An autoimmune condition where the body produces antibodies that increase blood clotting, potentially disrupting placental blood flow. APS is one of the most treatable causes of RPL — combination therapy with low-dose aspirin and heparin achieves approximately 74% live birth rates compared to 43% with aspirin alone. Testing requires detection of lupus anticoagulant, anticardiolipin antibodies, or anti-β2 glycoprotein I on two separate occasions at least 12 weeks apart.
Uterine Structural Abnormalities
Conditions that distort the uterine cavity and interfere with implantation or placentation. The most strongly associated anomaly is a uterine septum (a wall of tissue dividing the uterine cavity), which can be surgically corrected via hysteroscopy. Uterine fibroids, polyps, and intrauterine adhesions (Asherman's syndrome) can also contribute. Diagnosis requires imaging — sonohysterogram, hysteroscopy, or MRI.
Endocrine and Metabolic Disorders
Thyroid dysfunction — both overt hypothyroidism and subclinical thyroid disease (elevated TSH or thyroid peroxidase antibodies) are associated with increased miscarriage risk. Target TSH below 2.5 mIU/L during pregnancy. Uncontrolled diabetes increases miscarriage risk significantly — well-controlled diabetes does not. PCOS is associated with higher miscarriage rates, though the mechanism isn't fully understood.
Unexplained RPL
After a full workup, roughly half of RPL cases have no identifiable cause. This is frustrating — but it's important to know that the prognosis for unexplained RPL is actually favorable. Research consistently shows that 60–75% of women with unexplained recurrent loss will achieve a successful pregnancy with supportive care (early monitoring, progesterone support, emotional reassurance) and no specific medical intervention.
The RPL Workup: What Tests to Get
ASRM recommends evaluation after two or more pregnancy losses. Here's what a thorough workup includes — and what isn't worth testing:
Recommended Tests
| Test | What It Checks | Why It Matters |
|---|---|---|
| Antiphospholipid antibody panel | Lupus anticoagulant, anticardiolipin antibodies, anti-β2 glycoprotein I | APS is one of the most treatable causes; must be positive on two tests 12+ weeks apart |
| Parental karyotyping | Chromosomal structure of both partners | Identifies balanced translocations that increase aneuploid embryo risk |
| Thyroid panel | TSH, free T4, thyroid peroxidase (TPO) antibodies | Thyroid dysfunction is common and easily treatable |
| Uterine imaging | Sonohysterogram, hysteroscopy, or MRI | Identifies septum, fibroids, polyps, adhesions |
| Genetic testing of pregnancy tissue (POC) | 24-chromosome microarray of products of conception | Determines whether loss was chromosomally driven — critically helpful for directing next steps |
| Hemoglobin A1c or fasting glucose | Diabetes screening | Uncontrolled diabetes increases miscarriage risk |
| Prolactin | Serum prolactin levels | Elevated prolactin can interfere with implantation |
Generally NOT Recommended for Routine RPL Workup
- Hereditary thrombophilia testing (Factor V Leiden, MTHFR, prothrombin gene) — evidence does not support routine screening; treatment with anticoagulants hasn't improved outcomes in most studies
- Routine progesterone levels — not reliably predictive of future pregnancy outcomes
- TORCH serology — routine screening for infections (toxoplasmosis, rubella, CMV, herpes) is not useful in asymptomatic patients
- NK cell testing — blood or uterine natural killer cell counts are not clinically validated for RPL management; ASRM, ESHRE, and HFEA all advise against routine use
- Immune panels / cytokine profiles — not recommended for routine use; immunotherapy for RPL remains experimental
Some clinics offer extensive immune panels and NK cell testing as part of RPL evaluation, often leading to expensive immunotherapy treatments (intralipid infusions, steroids, IVIG). Major professional societies — including ASRM, ESHRE, and HFEA — do not recommend these tests or treatments as part of standard RPL care due to insufficient evidence. If offered, seek a second opinion.
What Treatments Actually Work?
Treatments with Strong Evidence
Antiphospholipid Syndrome → Aspirin + Heparin
The gold standard treatment for APS-associated RPL. Low-dose aspirin (81mg daily) combined with prophylactic heparin started early in pregnancy achieves approximately 74% live birth rates — significantly better than aspirin alone (43%). Treatment begins as soon as pregnancy is confirmed (or even before) and continues through delivery.
Uterine Septum → Hysteroscopic Metroplasty
Surgical removal of a uterine septum is a relatively straightforward outpatient procedure that can significantly reduce miscarriage rates. The septum is the most correctable uterine anomaly associated with RPL.
Thyroid Disorders → Levothyroxine
Thyroid hormone replacement for hypothyroidism is standard and effective. Target TSH below 2.5 mIU/L during pregnancy. When pregnancy is confirmed, levothyroxine dose is typically increased by two additional doses per week, with monitoring every 4–6 weeks.
Chromosomal Translocation → IVF with PGT-SR
When a parent carries a balanced translocation, IVF with preimplantation genetic testing for structural rearrangements (PGT-SR) can select embryos with normal chromosome arrangements, significantly reducing miscarriage risk.
Treatments with Limited or Mixed Evidence
Progesterone Supplementation
A meta-analysis of progesterone therapy in women with 3+ consecutive miscarriages showed a significant decrease in miscarriage rates. However, a large multicenter trial of high-dose vaginal progesterone from 6–12 weeks found no significant improvement. Current guidance suggests progesterone may help if started in the luteal phase (before pregnancy confirmation), but the evidence is mixed. Many clinicians prescribe it as supportive care with minimal risk.
IVF with PGT-A for RPL
PGT-A can select chromosomally normal embryos, potentially reducing per-transfer miscarriage rates. Some studies show improved outcomes in RPL patients, but a 2025 retrospective study found no significant difference in cumulative live birth rates between PGT-A and conventional IVF/ICSI in RPL patients. It may be most useful when combined with advanced maternal age.
Unexplained RPL: What Actually Helps
A systematic review found that under placebo conditions, 59% of women with unexplained RPL achieved live birth. With supportive care — early pregnancy monitoring, emotional support, and close clinical attention — success rates reach 60–75%. This is genuinely encouraging and often overlooked in clinical conversations focused on finding a cause.
For unexplained RPL, the evidence supports:
- Early pregnancy monitoring — early ultrasound confirmation of viability (6–8 weeks) and regular follow-up provides reassurance and allows early intervention if needed
- Supportive care and dedicated early pregnancy clinics — studies consistently show that emotional support and close clinical attention improve outcomes in unexplained RPL, possibly by reducing stress hormones
- Lifestyle optimization — reducing caffeine (under 200mg/day), avoiding smoking and alcohol, maintaining healthy BMI, and managing stress
- Progesterone supplementation — often prescribed as low-risk supportive therapy, starting in the luteal phase
- Pre-conception health optimization — supplements, nutrition, and lifestyle changes in the months before conceiving
The Emotional Side
RPL is one of the most emotionally devastating fertility experiences. The grief of recurrent loss is cumulative — each pregnancy carries both hope and dread. Couples dealing with RPL frequently experience anxiety, depression, relationship strain, and a profound sense of isolation that can intensify with each subsequent loss.
If you're going through this, a few things worth saying directly:
- It is not your fault. RPL is not caused by stress, exercise, working too hard, or anything you did or didn't do. The causes are biological, and the guilt that many patients carry is undeserved.
- Grief is appropriate and valid. Pregnancy loss — at any stage — is real loss. You don't need to minimize it or move past it on someone else's timeline.
- Professional support helps. Therapy with a reproductive psychologist or counselor who specializes in pregnancy loss can make a meaningful difference. Support groups — including organizations like RESOLVE and the Pregnancy After Loss Support community — connect you with people who understand what you're going through.
- The odds are in your favor. Even after three losses with no identified cause, the chance of a successful next pregnancy is approximately 60–75%. That number is higher than many patients expect or are told.
Supporting Your Next Pregnancy
→ More supplement and lifestyle guidance at LifeFertile.com
→ Emotional support and TTC resources at FertileStart.com
Frequently Asked Questions
RPL is defined as two or more pregnancy losses before 20 weeks gestation. It affects 1–5% of couples. ASRM recommends beginning evaluation after two losses. About 5% of women will experience two consecutive losses, and roughly 1% will have three or more.
Known causes include chromosomal abnormalities (~50–60% of individual losses), antiphospholipid syndrome (5–20% of RPL patients), uterine structural problems (10–15%), thyroid disorders, uncontrolled diabetes, and parental chromosomal translocations. Approximately 50% of RPL cases remain unexplained after full evaluation.
Key recommended tests include an antiphospholipid antibody panel, parental karyotyping, thyroid panel, uterine imaging, and potentially genetic testing of pregnancy tissue. Tests generally NOT recommended for routine screening include hereditary thrombophilia panels, NK cell testing, routine progesterone levels, and TORCH serology.
Treatable causes include antiphospholipid syndrome (aspirin + heparin, ~74% success), uterine septum (surgical correction), thyroid disorders (levothyroxine), and chromosomal translocations (IVF with PGT-SR). For unexplained RPL, supportive care with early monitoring and emotional support achieves 60–75% live birth rates.
PGT-A can reduce per-transfer miscarriage rates by selecting chromosomally normal embryos. However, recent evidence suggests it may not improve cumulative live birth rates for RPL patients overall. It may be most useful for RPL patients over 35 or those with confirmed chromosomal causes.
Better than most patients expect. After two losses: ~65–75% chance of success. After three losses with no identified cause: ~60–75%. With treatable causes like APS: ~70–80% with appropriate therapy. Even without treatment, the majority of women with RPL will eventually have a successful pregnancy.
Exploring Treatment Options?
Understand how IVF, PGT-A, and advanced testing can help after recurrent loss — plus every way to make treatment affordable.
PGT-A: Is It Worth It? →