Why am I having recurrent miscarriages? A clear medical explanation

By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group

Published: July 23, 2025Updated: July 23, 2025

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Key Takeaways

Most couples experience repeat pregnancy loss because of chromosomal problems in the embryo, undiagnosed maternal conditions such as antiphospholipid syndrome or poorly controlled thyroid disease, uterine structural issues, or modifiable lifestyle factors like tobacco use. A full work-up—genetic testing of both parents and pregnancy tissue, blood clotting panels, thyroid and hormonal labs, and detailed uterine imaging—identifies a cause in about 65 % of cases and guides targeted treatment.

What are the proven medical reasons for losing three or more pregnancies?

Recurrent miscarriage—defined as two consecutive pregnancy losses before 20 weeks—usually stems from identifiable medical issues rather than chance alone. Understanding the common causes allows you and your clinician to focus testing and treatment where it matters most.

Embryo chromosome errors are the top culpritUp to 60 % of early losses involve fetal aneuploidy such as trisomy 16; parental karyotype is abnormal in only 4 % of couples.
Uterine abnormalities disrupt implantationA septate uterus, fibroids deforming the cavity, or untreated Asherman scars account for about 15 % of repeat losses.
Blood-clotting disorders trigger placental failureAntiphospholipid syndrome triples the risk of miscarriage after 10 weeks by promoting tiny placental clots.
Endocrine issues create an inhospitable environmentEven mild thyroid under-function (TSH above 2.5 mIU/L) or poorly controlled diabetes doubles miscarriage odds.
Expert insight from the team at Eureka Health“When we test both parents, the embryo, and the uterus in a stepwise fashion, two-thirds of couples finally get a clear answer,” notes the team at Eureka Health.
Maternal age over 40 pushes miscarriage risk to around 40%NCCRM reports that the likelihood of miscarriage rises steadily with advancing age, reaching approximately 40 % by age 44, making age itself a major driver of recurrent loss. (NCCRM)
Up to half of recurrent loss cases remain unexplained even after testingUCSF Health states that despite thorough evaluation, no definite cause is identified in as many as 50 % of couples with recurrent pregnancy loss. (UCSF)

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Which red-flag symptoms mean I should seek urgent care during or after a loss?

Most miscarriages do not threaten the parent’s health, but certain signs demand immediate medical attention. Quick action reduces complications such as hemorrhage or infection.

Heavy bleeding soaking more than one pad an hourLoss of 500 mL or more can cause dizziness and low blood pressure—call emergency services.
Fever higher than 100.4 °F after tissue passesRetained products of conception raise sepsis risk; hospital evaluation and ultrasound are needed.
Severe one-sided pelvic painCould signal ectopic pregnancy; ultrasound should be performed within hours.
Passing grape-like tissue clustersMay indicate molar pregnancy, which requires prompt evacuation and hCG monitoring.
Quote from Sina Hartung, MMSC-BMI“Any miscarriage accompanied by fainting, severe pain, or foul discharge is a medical emergency, not a wait-and-see situation,” emphasizes Sina Hartung, MMSC-BMI.
Shoulder-tip pain and faintness can point to internal bleedingNHS warns that shoulder-tip pain combined with feeling very faint or light-headed may signal a ruptured ectopic pregnancy, which requires immediate emergency care. (NHS)
Passing gray tissue or large clots warrants prompt evaluationNYU Langone advises seeking urgent assessment if you pass blood clots or gray tissue along with bleeding or cramps, as these signs suggest incomplete miscarriage that may need surgical treatment. (NYU)

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How will my doctor pinpoint the root cause of repeat losses?

A structured evaluation done between pregnancies yields the highest diagnostic rate. Most tests are outpatient and covered by insurance when ordered for recurrent miscarriage.

Comprehensive parental karyotypeBalanced translocations found in 2-5 % of couples guide referral to in-vitro fertilization with genetic testing.
High-resolution transvaginal ultrasound or hysteroscopyDetects septum, polyps, or fibroids distorting the cavity with 90 % sensitivity.
Antiphospholipid antibody panel drawn twice 12 weeks apartPositive lupus anticoagulant or anti-β2-glycoprotein confirms APS and indicates anticoagulation in the next pregnancy.
Thyroid-stimulating hormone and thyroid antibodiesA TSH above 2.5 mIU/L or positive TPO antibodies prompts levothyroxine adjustment before conception.
Expert insight from the team at Eureka Health“Skipping the clotting and thyroid labs is the biggest diagnostic gap we see in primary care,” cautions the team at Eureka Health.
Chromosome analysis of miscarriage tissue reveals genetic errors in 50–70 % of lossesWhen such abnormalities are found, clinicians may steer couples toward IVF with pre-implantation genetic testing to reduce repeat miscarriage risk. (SGF)
Work-up often starts after two consecutive miscarriages to speed answers for the 1 % of women affectedMayo Clinic notes many physicians begin the evaluation after a second loss—despite older recommendations to wait for three—to shorten the time to diagnosis and treatment. (Mayo)

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What lifestyle changes improve my odds before the next pregnancy?

While medical treatment targets underlying disease, daily habits also influence embryo health and uterine readiness. Small, evidence-based adjustments can lower miscarriage risk by up to 20 %.

Achieve a body-mass index between 19 and 30Both underweight and obesity raise miscarriage odds; even a 5 % weight loss improves live-birth rates.
Stop tobacco and vaping entirelyNicotine impairs placental blood flow; cessation is linked to a 13 % lower loss rate in cohort studies.
Limit caffeine to under 200 mg dailyAbove this threshold the miscarriage rate climbs by 11 % per 100 mg increment.
Take 400 µg of folic acid dailyFolate supports DNA synthesis and reduces chromosomal breakage in early cell divisions.
Quote from Sina Hartung, MMSC-BMI“Clients who pair medical therapy with lifestyle changes often conceive within six months,” observes Sina Hartung, MMSC-BMI.
Skip alcohol entirely when trying to conceiveExpert guidance advises avoiding alcohol in the pre-conception period and during pregnancy because exposure is linked to higher miscarriage rates; complete abstinence is considered the safest choice. (Tommys)
Book a pre-pregnancy screen for infections and diabetesScreening for sexually transmitted infections and unrecognized diabetes before attempting conception allows timely treatment, which NYU Langone notes can improve implantation and lower early-pregnancy loss risk. (NYUL)

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Which labs and treatments actually improve live-birth rates?

Not every test or drug marketed for ‘pregnancy support’ is evidence-based. These investigations and interventions demonstrate the strongest data for recurrent miscarriage.

Low-dose aspirin plus heparin for antiphospholipid syndromeCombined therapy raises live-birth rates from 18 % to 71 % in randomized trials.
Levothyroxine titrated to keep TSH under 2.5 mIU/LNormalizing thyroid function cuts miscarriage risk nearly in half among women with subclinical hypothyroidism.
Surgical resection of uterine septum or cavity-distorting fibroidPost-operative live-birth rates exceed 80 % within one year.
Pre-implantation genetic testing (PGT-A) in IVF cyclesSelecting euploid embryos lowers miscarriage prevalence to 8 % per transfer in women over 38.
Expert insight from the team at Eureka Health“The best study design still favors aspirin-heparin for APS; immune suppressants have not shown similar effectiveness,” explains the team at Eureka Health.
Vaginal progesterone in early pregnancy benefits women with bleeding and multiple prior lossesThe Lancet review highlights the PRISM RCT, where 400 mg progesterone twice daily increased live-births from 57 % to 72 % among women with first-trimester bleeding and ≥3 previous miscarriages. (Lancet)
Prophylactic low-molecular-weight heparin yields 84 % live-birth in unexplained recurrent miscarriageIn a cohort of 164 women, LMWH therapy achieved an 83.8 % live-birth rate regardless of thrombophilia status—substantially above the expected 60 % without treatment. (SAGE)

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How can Eureka’s AI doctor support my miscarriage work-up?

Eureka’s platform blends evidence-based algorithms with human physician oversight, streamlining your path to answers and care.

Personalized test orderingThe AI suggests karyotype, antiphospholipid panel, and 3D ultrasound based on your history; board-certified doctors review before release.
Medication optimization remindersThe system flags high TSH or elevated HbA1c and prompts dose review within 24 hours.
Secure symptom trackingDaily logging of bleeding, cramps, and mood helps identify patterns the next time you conceive.
High user satisfactionWomen managing fertility issues on Eureka rate the app 4.8 out of 5 stars for accuracy and empathy.
Quote from Sina Hartung, MMSC-BMI“Eureka bridges the gap between specialist protocols and day-to-day support, so patients aren’t left waiting months for the next step,” says Sina Hartung, MMSC-BMI.

Why choose Eureka’s private, always-on AI doctor for future pregnancies?

Because recurrent miscarriage involves time-sensitive testing and early pregnancy monitoring, ready access to medical guidance is crucial. Eureka’s AI doctor is designed to meet that need without replacing your obstetrician.

24/7 triage with clinician back-upBleeding at 2 a.m.? The AI triages severity and, if needed, pages an on-call OB-GYN.
Integrated lab and imaging orderingUterine cavity ultrasound and APS panel can be scheduled directly through the app—no paper requisitions.
Data-driven treatment plansEach recommendation cites peer-reviewed studies and adjusts as new guidelines emerge.
Strict privacy safeguardsAll reproductive health data are encrypted end-to-end and never sold.
Quote from the team at Eureka Health“Our goal is simple: every woman with repeat loss deserves rapid answers and compassionate care, regardless of location,” affirms the team at Eureka Health.

Frequently Asked Questions

How many miscarriages count as recurrent miscarriage?

Most specialists start an evaluation after two consecutive losses, though insurance definitions sometimes require three.

Should my partner be tested as well?

Yes. A simple blood karyotype can reveal balanced translocations in either parent that lead to embryo chromosome errors.

Can I conceive naturally after being diagnosed with antiphospholipid syndrome?

Often yes. Low-dose aspirin plus injectible heparin during pregnancy results in healthy births for most women with APS.

Do progesterone supplements prevent miscarriage?

Large trials show no clear benefit in unexplained recurrent miscarriage, except possibly in women with documented luteal phase defect.

Is bed rest helpful after a positive pregnancy test?

No evidence supports routine bed rest; staying active improves circulation and mood without increasing risk.

Can my diet reduce chromosomal errors in eggs?

While diet cannot fix genetic nondisjunction, antioxidant-rich foods and adequate folate may support overall egg quality.

What is the success rate after uterine septum surgery?

Live-birth rates reach about 80 % within one year once the septum is resected.

How long should I wait to try again after a miscarriage?

If there are no complications, trying as soon as the next menstrual cycle is medically safe for most couples.

Does stress alone cause miscarriage?

Stress has not been proven to cause chromosome errors, but severe ongoing stress can worsen hormonal balance.

Will insurance pay for genetic testing of pregnancy tissue?

Coverage varies, but many plans cover chromosome microarray after two or more losses when ordered by a physician.

References

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