Recurrent Miscarriage

1. Clinical Overview

Summary

Recurrent Miscarriage (RM), also known as Recurrent Pregnancy Loss (RPL), represents one of the most distressing conditions in reproductive medicine, affecting approximately 1% of couples attempting to conceive. [1] The definition varies between international bodies: the Royal College of Obstetricians and Gynaecologists (RCOG) defines RM as three or more consecutive spontaneous pregnancy losses before 24 weeks of gestation, while the European Society of Human Reproduction and Embryology (ESHRE) uses a threshold of two or more losses to initiate investigation. [2,3]

Despite comprehensive evaluation, approximately 50% of cases remain unexplained (idiopathic RM), yet even these couples have a 60-75% chance of successful pregnancy with supportive care alone in subsequent attempts. [4] This remarkably positive prognosis forms a cornerstone of counselling.

The most important treatable cause is Antiphospholipid Syndrome (APS), accounting for approximately 15% of cases. [5] Without treatment, women with APS have pregnancy loss rates exceeding 90%, but with appropriate anticoagulation therapy (low-dose aspirin plus low-molecular-weight heparin), live birth rates increase to 70-80%. [6] This dramatic improvement makes APS screening mandatory in all women with RM.

Other identified causes include:

• Parental chromosomal abnormalities (3-5% of couples): Balanced translocations can produce chromosomally unbalanced embryos [7]
• Uterine anatomical abnormalities (10-15%): Septate uterus is the most common correctable anomaly [8]
• Endocrine disorders: Poorly controlled diabetes mellitus and thyroid dysfunction [9]
• Inherited thrombophilias: Controversial significance; routine screening NOT recommended by RCOG following negative trial evidence [10]

Recent evidence has transformed progesterone supplementation practice. The PRISM trial (2019) demonstrated that vaginal micronized progesterone (400mg BD) increases live birth rates in women with early pregnancy bleeding and a history of previous miscarriage, with the greatest benefit seen in those with three or more prior losses. [11] This led to NICE guideline updates recommending progesterone in this specific clinical scenario. [12]

Management is fundamentally cause-specific, but even when no cause is identified, structured supportive care—often termed "Tender Loving Care" (TLC)—including early pregnancy unit access, serial viability scans, and psychological support, significantly improves outcomes. [13]

The psychosocial impact of RM is profound, with high rates of anxiety, depression, and relationship strain. Integrated psychological support should be considered standard care for all affected couples. [14]

Clinical Pearls

"Three Strikes = Investigate" (RCOG) vs "Two Strikes" (ESHRE): In UK practice, formal investigation typically begins after three consecutive losses, though some specialists and international guidelines recommend initiating assessment after two losses, particularly in women of advanced maternal age (≥37 years) or with late pregnancy losses (12-24 weeks).

APS is the One NOT to Miss: Antiphospholipid Syndrome is the most important treatable cause of RM. Testing must be performed correctly—two positive tests at least 12 weeks apart—to confirm diagnosis according to Sydney revised criteria. The dramatic improvement in outcomes (from ~10% to ~70% live birth rate) makes this diagnosis critical.

"Most Couples Succeed Next Time": Even after three unexplained pregnancy losses, 60-75% of couples achieve live birth in the next pregnancy with supportive care alone. This positive message is crucial for counselling and often comes as a surprise to devastated couples.

Progesterone: Context Matters (PRISM vs PROMISE): Vaginal progesterone benefits women with bleeding in early pregnancy AND a history of miscarriage (PRISM trial). It does NOT help women with idiopathic RM who have no bleeding in the current pregnancy (PROMISE trial). Understanding this distinction is essential for appropriate use.

Lupus Anticoagulant is a Misnomer: Despite its name suggesting anticoagulation, lupus anticoagulant is actually prothrombotic, causing placental vessel thrombosis and pregnancy loss. It's detected by prolonged clotting tests (APTT) that don't correct with mixing studies.

Thrombophilia Screening: Not Routine: Following the ALIFE2 trial showing no benefit of LMWH in women with inherited thrombophilia and unexplained RM, routine thrombophilia screening is NOT recommended by RCOG. Testing should be reserved for those with personal or family history of venous thromboembolism.

Karyotype the Products, Not Just the Parents: When products of conception (POC) are available, karyotyping can distinguish between recurrent aneuploidy (random chromosomal errors, better prognosis) and recurrent euploidy losses (more likely to have an underlying maternal or placental cause requiring investigation).

Second Trimester Losses: Think Anatomy and Cervix: Losses between 12-24 weeks should prompt investigation for uterine anomalies and cervical insufficiency. These have different etiologies and management compared to early first-trimester losses.

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2. Epidemiology

Prevalence and Demographics

Age-Related Risk

Definitions and Classification

Distribution of Causes

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3. Aetiology and Pathophysiology

3.1 Antiphospholipid Syndrome (APS)

Prevalence: 15% of women with RM [5]

Pathophysiology

Antiphospholipid Syndrome is an acquired autoimmune thrombophilia characterized by the presence of antiphospholipid antibodies and clinical features of thrombosis and/or pregnancy morbidity.

Molecular Mechanisms:

1. Antibody Targets: Antibodies directed against phospholipid-binding proteins, particularly:

   • β2-glycoprotein I (β2GPI): Major antigenic target
   • Prothrombin
   • Cardiolipin-β2GPI complexes

2. Placental Thrombosis: Antibodies promote thrombosis in placental vessels through:

   • Activation of endothelial cells
   • Increased tissue factor expression
   • Platelet activation
   • Inhibition of natural anticoagulants (protein C, protein S, antithrombin)
   • Complement activation (C5a and C5b-9)

3. Defective Placentation: Beyond thrombosis, aPL antibodies:

   • Impair trophoblast invasion
   • Reduce trophoblast differentiation
   • Inhibit trophoblast syncytialization
   • Induce inflammatory cytokine release

4. Pregnancy Outcomes Without Treatment:

   • 90% pregnancy loss rate

   • Recurrent first-trimester losses
   • Late pregnancy losses (> 10 weeks)
   • Severe early-onset pre-eclampsia
   • Placental insufficiency and fetal growth restriction
   • Stillbirth

Diagnostic Criteria (Sydney Revised Criteria, 2006) [18]

Clinical Criteria (at least one):

• Vascular thrombosis: ≥1 episode of arterial, venous, or small vessel thrombosis
• Pregnancy morbidity:
  • ≥1 unexplained death of morphologically normal fetus ≥10 weeks, OR
  • ≥1 premature birth less than 34 weeks due to severe pre-eclampsia/placental insufficiency, OR
  • ≥3 unexplained consecutive spontaneous abortions less than 10 weeks (most relevant for RM)

Laboratory Criteria (at least one present on two or more occasions at least 12 weeks apart):

• Lupus anticoagulant (LA) detected according to ISTH guidelines
• Anticardiolipin antibody (aCL) IgG or IgM at medium-high titers (> 40 GPL or MPL, or > 99th percentile)
• Anti-β2-glycoprotein-I antibody IgG or IgM at titers > 99th percentile

Critical Point: Diagnosis requires persistent positivity—a single positive test is insufficient and may represent transient antibodies following infection.

Treatment

Evidence Base: Multiple RCTs and meta-analyses demonstrate benefit of anticoagulation in APS pregnancy [6]

Standard Treatment:

• Low-dose Aspirin 75-150mg once daily: Start when planning pregnancy or at positive pregnancy test; continue until delivery
• Low-molecular-weight heparin (LMWH):
  • Enoxaparin 40mg SC once daily OR
  • Dalteparin 5000 units SC once daily
  • Start at positive pregnancy test
  • Continue until 6 weeks postpartum (or longer if history of thrombosis)

Outcomes with Treatment:

• Live birth rate: 70-80% (vs ~10% untreated)
• Reduced rates of pre-eclampsia and growth restriction
• Reduced placental insufficiency

Monitoring in Pregnancy:

• Serial growth scans (every 2-4 weeks from 24 weeks)
• Umbilical artery Doppler assessment
• Preeclampsia surveillance (BP, urinalysis, symptoms)
• Platelet count monitoring on LMWH (heparin-induced thrombocytopenia is rare with LMWH but possible)

3.2 Parental Chromosomal Abnormalities

Prevalence: 3-5% of couples with RM (vs 0.7% in general population) [7]

Types of Abnormalities

Pathophysiology

Meiotic Segregation:

1. Parent with balanced translocation is phenotypically normal (correct gene dosage)

2. During meiosis, chromosomes can segregate in multiple ways:

   • Alternate segregation: Produces normal or balanced gametes (viable)
   • Adjacent-1 segregation: Produces unbalanced gametes (partial monosomy and trisomy)
   • Adjacent-2 segregation: Produces unbalanced gametes (rare)
   • 3:1 segregation: Produces severely unbalanced gametes

3. Most unbalanced conceptuses are lethal and result in miscarriage

4. Some may survive to term with congenital abnormalities (e.g., partial trisomies)

Investigation and Management

Investigation:

• Peripheral blood karyotype of both partners (using G-banded karyotyping)
• Products of conception (POC) karyotyping when available:
  • Distinguishes recurrent aneuploidy (random, sporadic) from recurrent euploidy losses (suggests parental or maternal cause)
  • Helps prognostication

Management Options:

1. Natural conception with prenatal diagnosis:

   • Chorionic villus sampling (CVS) at 11-13 weeks, OR
   • Amniocentesis at 15+ weeks
   • Allows early detection of unbalanced karyotypes
   • Option for termination if severe abnormality

2. Preimplantation Genetic Testing for Structural Rearrangements (PGT-SR):

   • IVF with embryo biopsy
   • Select chromosomally balanced or normal embryos for transfer
   • Reduces miscarriage risk
   • Does not necessarily improve live birth rate per cycle (many embryos are abnormal)
   • Expensive; not universally available on NHS

3. Donor gametes: In severe translocations or recurrent failures

Genetic Counseling: Essential to:

• Explain inheritance patterns
• Discuss reproductive options
• Address family implications (siblings, children)
• Provide psychological support

3.3 Uterine Anatomical Abnormalities

Prevalence: 10-15% in RM populations (vs 5-7% in general population) [8]

Types and Mechanisms

Septate Uterus Pathophysiology

The septate uterus is the most common congenital uterine anomaly associated with RM and the only one with strong evidence for surgical correction improving outcomes.

Mechanism:

• Septum is composed of fibrous or fibromuscular tissue with poor vascularity
• Embryo implanting on septum receives inadequate blood supply
• Results in:
  • Failed implantation
  • Early pregnancy loss (most common)
  • Preterm birth (if pregnancy continues)
  • Malpresentation

Diagnosis:

• 3D ultrasound or MRI pelvis: Gold standard to distinguish septate from bicornuate uterus
  • "Septate: Single external uterine contour; internal septum"
  • "Bicornuate: Indentation of external uterine contour > 1cm"
• Hysteroscopy: May see septum but cannot assess external contour
• Saline infusion sonography (SIS): Alternative to 3D USS

Treatment:

• Hysteroscopic metroplasty (septal resection)
• Day-case procedure
• Low complication rate
• Improves live birth rate from ~30% to ~80% in observational studies [19]
• No RCT evidence (deemed unethical given strong observational data)

Submucosal Fibroids

Mechanism:

• Distortion of endometrial cavity
• Altered endometrial receptivity
• Abnormal uterine contractility
• Local inflammatory response

Evidence: Observational data suggest hysteroscopic myomectomy improves outcomes for submucosal fibroids causing RM, though RCT evidence is limited.

Asherman's Syndrome

Causes:

• Endometrial trauma (dilatation and curettage, particularly multiple procedures)
• Endometritis
• Previous uterine surgery

Mechanism: Intrauterine adhesions reduce functional endometrial surface area

Treatment: Hysteroscopic adhesiolysis followed by hormonal suppression (estrogen) to promote re-epithelialization

3.4 Endocrine Factors

Thyroid Dysfunction

Association with RM:

• Overt hypothyroidism and hyperthyroidism: Clearly increase miscarriage risk [9]
• Subclinical hypothyroidism: Controversial; some studies show association
• Thyroid antibodies (anti-TPO, anti-thyroglobulin): May increase risk independent of TSH level

Mechanism:

• Inadequate thyroid hormone for fetal neurodevelopment
• Autoimmune thyroid disease may reflect broader immune dysregulation
• Thyroid antibodies may be a marker for reproductive immune dysfunction

Management:

• Target TSH less than 2.5 mIU/L in early pregnancy (ATA and Endocrine Society guidelines)
• Levothyroxine supplementation for hypothyroidism
• Consider levothyroxine even if TSH normal but antibody-positive (controversial; some RCTs show benefit)

Diabetes Mellitus

Evidence:

• Poorly controlled diabetes (HbA1c > 6.5%/48 mmol/mol) increases miscarriage risk 2-3 fold
• Well-controlled diabetes: Risk approaches baseline

Mechanism:

• Hyperglycemia causes oxidative stress
• Advanced glycation end products
• Vascular dysfunction
• Increased fetal anomaly risk

Management:

• Pre-conception optimization (HbA1c less than 48 mmol/mol ideally)
• Tight glycemic control in pregnancy

Polycystic Ovary Syndrome (PCOS)

Controversy: Association with RM is debated

• Some studies show increased risk; others do not
• Confounded by obesity, insulin resistance, and higher age at conception
• Metformin in PCOS pregnancy: No proven benefit for reducing miscarriage (multiple RCTs negative)

3.5 Inherited Thrombophilias

Controversies: This is the most controversial area in RM investigation and management.

Common Inherited Thrombophilias

Evidence Against Routine Screening

ALIFE2 Trial (2021) [10]:

• RCT of women with inherited thrombophilia and unexplained RM
• Compared LMWH vs no LMWH
• No difference in live birth rate (44% vs 47%)
• Conclusion: LMWH does not improve outcomes in inherited thrombophilia and RM

Current RCOG Position [2]:

• Routine thrombophilia screening NOT recommended
• Testing may be considered in:
  • Personal history of VTE
  • Family history of VTE (first-degree relative)
  • Stillbirth
  • Severe early-onset pre-eclampsia
  • Placental abruption

Pathophysiology (if association exists):

• Placental microthrombosis
• Impaired placental perfusion
• Most losses likely occur very early (implantation failure)

3.6 Immunological Factors

Controversial Area: Beyond APS, the role of immunological factors in RM is highly controversial.

Proposed Mechanisms (NOT PROVEN)

"Alloimmune" Theories:

• Excessive maternal immune response against paternal antigens
• Failure of maternal tolerance mechanisms
• Abnormal NK cell activity

Reality:

• No proven benefit of immunomodulatory therapies (IVIg, steroids, intralipid, paternal cell immunization)
• RCOG and ESHRE recommend AGAINST these treatments [2,3]
• Many private clinics offer these as "immune therapies"—should be avoided outside research trials

3.7 Unexplained/Idiopathic RM (50% of Cases)

Despite accounting for half of all cases, unexplained RM has the best prognosis: 60-75% live birth rate with supportive care alone. [4]

Possible Contributing Factors (unproven or difficult to test):

• Implantation defects
• Subtle endometrial receptivity abnormalities
• Recurrent aneuploidy (chance, particularly with advancing age)
• Undetected embryonic abnormalities
• Poorly understood immune mechanisms
• Male factor (sperm DNA fragmentation—controversial)

Psychological and Placebo Effect:

• "Tender Loving Care" (TLC) clinic model shows improved outcomes
• Early pregnancy unit access
• Serial scans for reassurance
• Psychological support
• Possible mechanisms: reduced stress, increased monitoring, earlier detection of complications

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4. Clinical Presentation

4.1 History Taking

A detailed, empathetic history is crucial. Couples presenting with RM are often devastated and anxious.

Pregnancy History

Medical History

Surgical History

Family History

Social and Lifestyle History

Psychological Assessment

Essential to assess:

• Anxiety and depression (very common)
• Relationship strain
• Previous psychological support
• Coping mechanisms
• Support network

4.2 Physical Examination

Physical examination in RM is usually unrevealing but should assess for:

Note: Structural uterine abnormalities and cervical insufficiency are not detectable on routine pelvic examination and require imaging/specialized assessment.

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5. Investigations

Investigation should be systematic and evidence-based. Avoid over-investigation with tests lacking proven clinical utility.

5.1 Recommended Investigations (RCOG/ESHRE)

Antiphospholipid Antibody Testing

ESSENTIAL investigation in all women with RM.

Critical Requirements:

• TWO positive tests at least 12 weeks apart (Sydney criteria)
• Timing: Test when not pregnant and ideally not on anticoagulation
• Single positive test = NOT diagnostic; may be transient (post-viral)

Practical Points:

• LA testing affected by anticoagulants (warfarin, LMWH)
• If LA testing required on anticoagulation, discuss with hematology
• Test both IgG and IgM for aCL and anti-β2GPI

Parental Karyotyping

Indications: All couples with RM (RCOG); some centers test after 2 losses

Interpretation:

• Normal karyotypes: Reassuring but does not exclude embryonic aneuploidy (which is usually sporadic)
• Abnormal: Refer to Clinical Genetics for counseling regarding reproductive options

Products of Conception (POC) Karyotyping (if available):

• Provides valuable information
• Recurrent aneuploidy: Suggests sporadic chromosomal errors (better prognosis)
• Recurrent normal karyotype losses: Suggests maternal/placental cause (requires investigation)

Pelvic Imaging for Uterine Assessment

Objective: Identify structural uterine abnormalities

Recommended Approach:

• Start with 2D TVUSS (routine)
• If abnormality suspected or RM workup: 3D USS or MRI
• Hysteroscopy if cavity abnormality on imaging or for treatment

Endocrine Investigations

PCOS Testing: Not routinely recommended unless investigating subfertility

Inherited Thrombophilia Screening

RCOG Recommendation: NOT routine [2]

Consider testing ONLY if:

• Personal history of VTE
• First-degree relative with VTE (especially if unprovoked or age less than 50)
• History of stillbirth
• Severe early-onset pre-eclampsia (less than 34 weeks)
• Placental abruption

Tests (if indicated):

• Factor V Leiden mutation
• Prothrombin G20210A mutation
• Protein C, Protein S, Antithrombin levels (ideally when not pregnant/on anticoagulants)

Important: Even if inherited thrombophilia detected, LMWH does not improve live birth rate in RM (ALIFE2 trial) [10]

5.2 Investigations NOT Recommended

The following have insufficient evidence and should NOT be routinely performed:

Beware: Many private clinics offer extensive "immune" and "genetic" panels with no evidence base. Stick to guidelines.

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6. Management

Management is etiology-specific. Even in unexplained RM, supportive care is evidence-based and effective.

6.1 General Principles

Pre-Conception Counseling

All Couples:

• Folic acid 400 mcg daily (5mg if previous neural tube defect, diabetes, anti-epileptics)
• Lifestyle modification:
  • Stop smoking
  • Reduce alcohol (less than 1-2 units/week or abstain)
  • Optimize BMI (18.5-25)
  • Moderate caffeine (less than 200mg/day)
• Screen for rubella immunity and offer MMR if non-immune (wait 1 month before conceiving)
• Optimize medical conditions: Diabetes, hypertension, thyroid disease

Psychological Support

Essential Component of Care:

• Acknowledge grief and loss
• Provide access to counseling services
• Offer peer support groups
• Involve partners in consultations
• Normalize anxiety about subsequent pregnancies

Evidence: "Tender Loving Care" clinics with psychological support show improved live birth rates even in unexplained RM [13]

6.2 Cause-Specific Management

Antiphospholipid Syndrome

Treatment Protocol:

Pre-Conception:

• Low-dose aspirin 75-150mg once daily
• Start when planning pregnancy or at positive pregnancy test

Once Pregnancy Confirmed (positive urinary pregnancy test or serum βhCG):

• Continue aspirin
• Add LMWH:
  • Enoxaparin 40mg SC once daily, OR
  • Dalteparin 5000 units SC once daily
  • Continue until at least 6 weeks postpartum

Monitoring:

• Early viability scan (6-7 weeks)
• Dating scan (11-13 weeks)
• Serial fetal growth scans from 24 weeks (every 2-4 weeks)
• Umbilical artery Doppler from 24 weeks
• Preeclampsia surveillance (BP, urinalysis, symptoms)
• Platelet monitoring (baseline, then monthly or if concerns re HIT)

Delivery:

• Timing individualized; often 37-38 weeks if complications
• Stop LMWH 24 hours before planned delivery (regional anesthesia)
• Can restart 4-6 hours after delivery (or per obstetric anesthesia guidance)

Evidence: Multiple RCTs and meta-analyses demonstrate 70-80% live birth rate with aspirin + LMWH vs ~10% untreated [6]

Postpartum:

• Continue LMWH for 6 weeks postpartum (VTE risk period)
• If history of thrombosis: consider 6 months or longer anticoagulation (discuss with hematology)

Parental Chromosomal Abnormalities

Management: Referral to Clinical Genetics

Options:

1. Natural Conception with Prenatal Diagnosis:

   • Chorionic villus sampling (CVS) at 11-13 weeks, OR
   • Amniocentesis at 15-16 weeks
   • Karyotype fetus
   • Option for termination if severe unbalanced abnormality
   • Reassurance: Many couples with translocations achieve healthy pregnancies

2. Preimplantation Genetic Testing for Structural Rearrangements (PGT-SR):

   • IVF cycle
   • Embryo biopsy at blastocyst stage
   • Test for translocation
   • Transfer chromosomally balanced or normal embryos
   • Reduces miscarriage risk but may not improve cumulative live birth rate
   • Expensive; limited NHS availability

3. Donor Gametes: In severe cases or recurrent failures

Genetic Counseling Topics:

• Explanation of translocation
• Risk quantification (varies by translocation type)
• Reproductive options
• Implications for existing children and family members
• Psychological support

Uterine Structural Abnormalities

Septate Uterus:

• Hysteroscopic metroplasty (septal resection)
• Day-case or overnight stay
• Low complication rate
• Improves live birth rate from ~30% to ~80% [19]
• Pregnancy advised to wait 2-3 months post-operatively

Submucosal Fibroids:

• Hysteroscopic myomectomy if distorting cavity
• Evidence base moderate but observational data supportive

Intrauterine Adhesions (Asherman's Syndrome):

• Hysteroscopic adhesiolysis
• Postoperative estrogen therapy to promote endometrial regeneration
• Second-look hysteroscopy to assess for re-formation
• Pregnancy outcomes variable depending on severity

Bicornuate/Unicornuate/Didelphys:

• Generally no surgical intervention
• Counsel regarding increased risk of preterm birth and malpresentation
• No proven benefit of surgery for these anomalies

Cervical Insufficiency (second-trimester losses):

• Cervical cerclage (McDonald or Shirodkar suture) at 13-16 weeks
• Indications:
  • History of second-trimester loss with cervical dilatation
  • Short cervix on ultrasound (less than 25mm at 18-22 weeks)
• Remove at 36-37 weeks or in labor

Endocrine Disorders

Hypothyroidism:

• Levothyroxine to achieve TSH less than 2.5 mIU/L pre-conception and in early pregnancy
• Increase dose by 25-30% as soon as pregnancy confirmed
• Monitor TSH every 4 weeks in first trimester, then each trimester

Thyroid Antibody Positivity with Normal TSH:

• Controversial
• Some evidence for levothyroxine reducing miscarriage
• Consider treatment on case-by-case basis

Diabetes Mellitus:

• Pre-conception optimization: HbA1c target less than 48 mmol/mol (less than 6.5%)
• Tight glycemic control in pregnancy
• Early viability and anomaly scans

PCOS:

• Metformin: No proven benefit for reducing miscarriage in PCOS
• Weight loss if BMI > 30
• No specific intervention for RM

Inherited Thrombophilia

Current Evidence (ALIFE2 Trial) [10]: LMWH does NOT improve live birth rate

RCOG Recommendation:

• Do NOT offer LMWH solely for inherited thrombophilia in RM
• Exception: If personal history of VTE, then anticoagulate for VTE prevention (not RM treatment)

Counseling:

• Reassure regarding prognosis with supportive care
• Avoid unnecessary anticoagulation and its risks
• Discuss VTE risk in pregnancy and puerperium

6.3 Unexplained Recurrent Miscarriage (50% of Cases)

Despite no identifiable cause, prognosis is good: 60-75% live birth rate with supportive care alone. [4]

Evidence-Based Supportive Care

"Tender Loving Care" (TLC) Clinic Model [13]:

• Dedicated recurrent miscarriage clinic
• Continuity of care
• Early pregnancy unit access
• Serial transvaginal ultrasound scans:
  • 6 weeks: confirm intrauterine pregnancy, fetal pole
  • 7-8 weeks: confirm fetal heartbeat
  • 9-10 weeks: ongoing viability
  • 12 weeks: dating scan (routine)
• Psychological support and reassurance
• Direct telephone access to specialist team

Evidence: Observational studies show this approach improves live birth rates compared to no specific care, possibly through:

• Reduced anxiety and stress
• Earlier detection of complications
• Placebo/supportive effect
• Increased compliance with healthy behaviors

Progesterone Supplementation

Context-Dependent Efficacy:

PRISM Trial (2019) [11]:

• RCT of vaginal micronized progesterone 400mg BD vs placebo
• Population: Women with bleeding in early pregnancy (threatened miscarriage) AND history of previous miscarriage
• Outcome: Increased live birth rate (75% vs 72%, absolute increase 3-5%)
• Subgroup analysis: Greatest benefit in women with ≥3 prior losses (live birth 72% vs 57%)

PROMISE Trial (2015) [20]:

• RCT of vaginal progesterone vs placebo
• Population: Women with unexplained RM, NO bleeding in current pregnancy
• Outcome: No difference in live birth rate (66% vs 63%)

Interpretation:

• Progesterone helps only in women with bleeding in current pregnancy + history of miscarriage
• Does NOT help unexplained RM without bleeding

NICE Guideline (NG126) [12]:

• Recommends progesterone 400mg BD vaginally in women with bleeding and prior miscarriage
• Start as soon as bleeding occurs
• Continue until 16 weeks gestation

Practical Use:

• Do NOT offer routine progesterone to all women with RM
• Offer if bleeding develops in early pregnancy
• Prescribe vaginal micronized progesterone 400mg twice daily (e.g., Utrogestan, Cyclogest)

Other Interventions in Unexplained RM

Warning: Many private clinics offer "immune therapies" (IVIg, intralipid, steroids) at high cost with no evidence of benefit and potential for harm. RCOG and ESHRE explicitly recommend against these treatments. [2,3]

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7. Complications and Prognosis

7.1 Psychological Complications

Recurrent miscarriage has profound psychological impact:

Screening: Use validated tools (e.g., GAD-7, PHQ-9) at RM clinic and in early pregnancy

Support:

• Miscarriage Association (UK charity): Telephone helpline, online forum, leaflets
• Tommy's (UK charity): Research and support for pregnancy loss
• Peer support groups
• Professional counseling (NHS or private)

7.2 Obstetric Complications in Subsequent Pregnancies

Even successful pregnancies after RM have increased risks:

Monitoring in Subsequent Pregnancies:

• Early viability scans (6-8 weeks)
• Dating scan (11-13 weeks)
• Anomaly scan (18-20 weeks)
• Serial growth scans from 24-28 weeks (especially if APS or previous complications)
• Consider aspirin 150mg OD from 12 weeks if risk factors for pre-eclampsia

7.3 Prognosis by Scenario

Live Birth Rates by Number of Prior Losses

Key Message: Even after multiple losses, the next pregnancy is more likely to succeed than fail.

Live Birth Rates by Underlying Cause

Factors Affecting Prognosis

Positive Prognostic Factors:

• Younger maternal age (less than 35 years)
• Secondary RM (previous live birth)
• Shorter interval between losses and next pregnancy
• Treatable cause identified (especially APS, septate uterus)

Negative Prognostic Factors:

• Advanced maternal age (> 40 years)
• ≥5 prior losses
• Primary RM (no previous live births)
• Advancing paternal age

Maternal Age Effect:

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8. Evidence and Guidelines

8.1 Key Guidelines

8.2 Landmark Trials and Evidence

PRISM Trial (2019) [11]

Design: Multi-center, double-blind, placebo-controlled RCT

Population: 4,153 women with bleeding in early pregnancy

Intervention: Vaginal micronized progesterone 400mg BD vs placebo

Primary Outcome: Live birth rate

Results:

• Overall: 75% live birth (progesterone) vs 72% (placebo) — small but significant benefit
• Subgroup with ≥3 prior miscarriages: 72% vs 57% — substantial benefit
• Number needed to treat (NNT) in women with ≥3 prior losses: ~7

Conclusion: Progesterone beneficial in women with bleeding + prior miscarriage, especially if ≥3 losses

Impact: Led to NICE guideline change recommending progesterone in this scenario

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PROMISE Trial (2015) [20]

Design: Multi-center, double-blind, placebo-controlled RCT

Population: 836 women with unexplained RM, NO bleeding in current pregnancy

Intervention: Vaginal micronized progesterone 400mg BD vs placebo

Primary Outcome: Live birth rate

Results: 66% vs 63% (NOT statistically significant)

Conclusion: Progesterone does NOT improve outcomes in unexplained RM without bleeding

Impact: Established that progesterone is context-dependent (bleeding required for benefit)

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ALIFE2 Trial (2021) [10]

Design: Open-label RCT

Population: 326 women with inherited thrombophilia and unexplained RM

Intervention: LMWH (enoxaparin 40mg daily) vs no LMWH

Primary Outcome: Live birth rate

Results: 44% (LMWH) vs 47% (no LMWH) — no significant difference

Conclusion: LMWH does NOT improve live birth rate in inherited thrombophilia and RM

Impact:

• RCOG changed guidelines to recommend AGAINST routine thrombophilia screening
• LMWH not recommended for unexplained RM or inherited thrombophilia

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Meta-Analysis: Aspirin + LMWH in APS (2020) [6]

Design: Systematic review and meta-analysis of RCTs

Population: Women with APS and pregnancy

Intervention: Aspirin + LMWH vs aspirin alone or no treatment

Results:

• Live birth rate 70-80% with aspirin + LMWH
• Significant reduction in pregnancy loss compared to no treatment
• Aspirin alone inferior to aspirin + LMWH

Conclusion: Aspirin + LMWH is gold standard for APS in pregnancy

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Hysteroscopic Metroplasty for Septate Uterus (2010 Meta-Analysis) [19]

Design: Systematic review of observational studies (no RCTs)

Population: Women with septate uterus and RM

Intervention: Hysteroscopic septal resection

Results:

• Live birth rate ~80% post-metroplasty vs ~30% untreated
• Low complication rate

Conclusion: Observational data strongly support metroplasty for septate uterus in RM

Note: RCT considered unethical given strength of observational evidence

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9. Examination Focus

9.1 High-Yield MRCOG Exam Topics

Definitions (Part 1 SBAs)

Q: Which definition of recurrent miscarriage is used by RCOG?

• A) ≥2 consecutive losses
• B) ≥3 consecutive losses ✅
• C) ≥2 losses (not necessarily consecutive)
• D) ≥4 losses
• E) ≥3 losses after one live birth

Answer: B — RCOG defines RM as ≥3 consecutive losses before 24 weeks (ESHRE uses ≥2)

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Most Important Treatable Cause (Part 2 SBAs, Orals)

Q: What is the most important treatable cause of recurrent miscarriage?

• A) Inherited thrombophilia
• B) Parental balanced translocation
• C) Antiphospholipid Syndrome ✅
• D) Uterine septum
• E) Hypothyroidism

Answer: C — APS is the most important treatable cause with dramatic improvement in outcomes (70-80% live birth with treatment vs ~10% untreated)

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APS Diagnostic Criteria (Part 2)

Q: A 32-year-old woman with 3 miscarriages has positive lupus anticoagulant. What is required before diagnosing APS?

• A) Immediate treatment with LMWH
• B) Repeat test in 4 weeks
• C) Repeat test in 12 weeks ✅
• D) Additional thrombophilia screen
• E) Genetic counseling

Answer: C — Sydney criteria require TWO positive tests at least 12 weeks apart to diagnose APS

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Progesterone (Part 2, Common SBA)

Q: In which scenario is progesterone most likely to improve outcomes in a woman with 3 prior miscarriages?

• A) Started pre-conception in all women with RM
• B) Started at positive pregnancy test in all women with RM
• C) Started if bleeding develops in early pregnancy ✅
• D) Started in second trimester
• E) Not indicated in recurrent miscarriage

Answer: C — PRISM trial: progesterone (400mg BD vaginally) benefits women with bleeding + prior miscarriage

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Thrombophilia Screening (Part 2)

Q: A 28-year-old woman with 3 unexplained miscarriages asks about thrombophilia testing. What is the most appropriate management?

• A) Test for Factor V Leiden and Prothrombin G20210A
• B) Arrange full thrombophilia screen
• C) Explain routine screening NOT recommended ✅
• D) Start LMWH empirically
• E) Test only if family history of miscarriage

Answer: C — RCOG does NOT recommend routine thrombophilia screening after ALIFE2 trial (no benefit of LMWH)

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9.2 Oral Examination (Part 3) — Viva Scenarios

Scenario 1: APS Management

Examiner: "A 34-year-old woman has had 4 consecutive first-trimester miscarriages. Her lupus anticoagulant is positive on two occasions 14 weeks apart. Anticardiolipin and anti-β2GP1 antibodies are negative. She is not currently pregnant. How would you counsel her?"

Model Answer:

"This woman meets diagnostic criteria for Antiphospholipid Syndrome based on the clinical criterion of ≥3 unexplained consecutive losses before 10 weeks and persistent lupus anticoagulant positivity on two occasions > 12 weeks apart.

Prognosis: Without treatment, pregnancy loss rate exceeds 90%. With appropriate treatment—low-dose aspirin and LMWH—live birth rate is 70-80%.

Pre-Conception:

• Start aspirin 75-150mg once daily when planning pregnancy
• Provide pre-conception counseling: folic acid, lifestyle optimization
• Ensure rubella immunity

Management Once Pregnant:

• Continue aspirin
• Start LMWH (enoxaparin 40mg SC daily or dalteparin 5000 units SC daily) as soon as pregnancy test positive
• Early viability scan at 6-7 weeks
• Serial growth scans from 24 weeks every 2-4 weeks
• Umbilical artery Doppler surveillance
• Pre-eclampsia surveillance (BP, urinalysis)

Postpartum:

• Continue LMWH for 6 weeks postpartum
• Stop LMWH 24 hours before planned delivery for regional anesthesia
• Can restart 4-6 hours post-delivery

Counseling Points:

• Excellent prognosis with treatment
• Need for daily injections throughout pregnancy
• Increased monitoring
• Small risk of heparin-induced thrombocytopenia (monitor platelets)
• VTE risk in pregnancy and puerperium"

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Scenario 2: Unexplained RM

Examiner: "A 30-year-old woman has had 3 consecutive miscarriages at 7, 8, and 9 weeks. Full investigation including APS screen, parental karyotyping, pelvic imaging, and thyroid function are all normal. She is devastated and asks 'will I ever have a baby?' What do you tell her?"

Model Answer:

"I would provide realistic optimism based on evidence.

Prognosis:

• Even after 3 unexplained miscarriages, 60-75% of women achieve live birth in the next pregnancy with supportive care alone
• This means the next pregnancy is more likely to succeed than fail
• Each loss does not further worsen prognosis substantially until > 5 losses

Management Plan:

1. Pre-Conception:

   • Folic acid 400mcg daily
   • Lifestyle: stop smoking, reduce alcohol, optimize BMI
   • Psychological support: acknowledge losses, offer counseling

2. Early Pregnancy:

   • Early access to recurrent miscarriage clinic
   • Serial viability scans: 6 weeks, 7-8 weeks (confirm heartbeat), 9-10 weeks
   • Direct telephone access for reassurance
   • If bleeding occurs: start vaginal progesterone 400mg BD (PRISM trial evidence) until 16 weeks

3. Ongoing Pregnancy:

   • Standard antenatal care
   • Consider serial growth scans (slight increased risk of complications)

Psychological Support:

• Validate her grief and anxiety
• Explain "Tender Loving Care" clinic model improves outcomes
• Offer access to Miscarriage Association, Tommy's
• Involve partner

Key Message: The evidence is genuinely reassuring—the majority of women in her situation go on to have a baby."

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Scenario 3: Parental Translocation

Examiner: "A couple with 3 miscarriages undergo karyotyping. The male partner has a balanced reciprocal translocation t(11;22). What are their options?"

Model Answer:

"I would refer to Clinical Genetics for detailed counseling, but I can outline the key points:

Explanation:

• The father has a balanced translocation involving chromosomes 11 and 22
• He has normal total genetic material, so he is healthy
• During sperm production (meiosis), chromosomes can segregate in different ways
• This can produce:
  • Normal or balanced sperm (viable pregnancy)
  • Unbalanced sperm with missing or extra chromosomal segments (miscarriage or abnormality)

Reproductive Options:

1. Natural Conception with Prenatal Diagnosis:

   • Try naturally
   • Prenatal testing via CVS (11-13 weeks) or amniocentesis (15+ weeks)
   • If fetus has unbalanced karyotype → option for termination
   • Many couples with translocations achieve successful pregnancies naturally

2. IVF with Preimplantation Genetic Testing (PGT-SR):

   • IVF cycle
   • Embryo biopsy at blastocyst stage
   • Test embryos for translocation
   • Transfer only balanced or normal embryos
   • Reduces miscarriage risk
   • Does NOT necessarily improve live birth rate per cycle (high proportion of embryos abnormal)
   • Expensive; limited NHS funding

3. Donor Sperm: If above options unsuccessful or unacceptable

Prognosis:

• Variable depending on specific translocation
• Many couples achieve successful pregnancies (40-80% depending on translocation type)

Other Considerations:

• Implications for existing children (may carry translocation)
• Extended family screening may be offered
• Psychological support

Next Steps: Refer to Clinical Genetics for specialized counseling and discussion of PGT-SR access."

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9.3 Common Pitfalls and Mistakes

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10. Patient and Layperson Explanation

Why do miscarriages happen?

Most early miscarriages (before 12 weeks) happen because of random genetic errors in the embryo—nature's quality control. This is usually a one-off event and is NOT caused by anything you did—not stress, exercise, lifting, sex, or that glass of wine before you knew you were pregnant.

As women get older (especially over 35), the eggs are more likely to have these genetic errors, which is why miscarriage becomes more common with age.

Why do I keep miscarrying?

When someone has three or more miscarriages in a row, doctors call this "recurrent miscarriage." It's rare—it affects about 1 in 100 couples.

The frustrating truth is that even after detailed tests, we can't find a cause in about half of cases. But here's the really important part: even when we don't find a cause, about 3 out of 4 women (60-75%) go on to have a healthy baby in their next pregnancy with supportive care.

What causes recurrent miscarriage?

When we do find a cause, the most common are:

1. "Sticky blood" (Antiphospholipid Syndrome or APS):

   • The body makes antibodies that cause tiny blood clots in the placenta
   • This is the most important cause to find because we can treat it very effectively
   • Treatment with aspirin tablets and blood-thinning injections increases the chance of success from about 10% to 70-80%

2. Genetic rearrangement in a parent:

   • One partner may carry a "balanced translocation"—their chromosomes are rearranged but they're completely healthy
   • However, this can produce embryos with the wrong amount of genetic material, causing miscarriage
   • Specialist genetic doctors can discuss options

3. Shape of the womb (uterus):

   • Some women have a wall of tissue dividing the womb (called a "septate uterus")
   • A simple keyhole surgery to remove this can help

4. Thyroid or diabetes problems:

   • If not well-controlled, these can increase miscarriage risk
   • Getting them under control before pregnancy helps

What tests will I have?

Your doctor will usually recommend:

• Blood tests:

  • "Sticky blood" tests (antiphospholipid antibodies)—done twice, 12 weeks apart
  • Thyroid function
  • Blood sugar (diabetes check)

• Genetic tests (blood test from both partners):

  • Check for chromosome rearrangements

• Ultrasound scan (or MRI):

  • Check the shape of your womb

What treatment can you offer?

It depends on what we find:

What about progesterone?

You may have heard about progesterone treatment. Here's what the research shows:

• If you have bleeding in early pregnancy and a history of miscarriage, progesterone pessaries (inserted into the vagina) can help—this is now recommended by NICE
• If you don't have bleeding, progesterone doesn't help
• So we offer it only if bleeding starts in the pregnancy

Will I ever have a baby?

Yes—most women with recurrent miscarriage DO go on to have a baby.

Even after three miscarriages with no cause found, about 60-75% of women succeed in the next pregnancy. The next pregnancy is more likely to succeed than fail.

If we find a treatable cause like "sticky blood" (APS) or a womb shape problem, the success rate is even higher with treatment (70-80%).

What can I do to help?

• Stop smoking (smoking increases miscarriage risk)
• Reduce alcohol (especially in early pregnancy)
• Folic acid 400 micrograms daily (start before pregnancy)
• Healthy weight (very high or very low BMI can affect pregnancy)
• Reduce caffeine (less than 2 cups of coffee per day)

What support is available?

Recurrent miscarriage is emotionally devastating. It's completely normal to feel anxious, sad, or even traumatized. Support available includes:

• Recurrent miscarriage clinic: Specialist doctors and nurses who understand what you're going through
• Early pregnancy scans: To reassure you when you do get pregnant
• Counseling: To help with the emotional impact
• Charities: Like the Miscarriage Association and Tommy's—they have helplines and support groups
• Your partner: Involve them; this affects both of you

"Is it my fault?"

NO. Recurrent miscarriage is not caused by:

• Stress
• Working
• Exercise
• Sex
• Lifting
• A fright or shock
• Something you ate or drank before you knew you were pregnant

It's a medical condition, and it's not your fault.

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11. References

Primary Sources

1. Rai R, Regan L. Recurrent miscarriage. Lancet. 2006;368(9535):601-611. doi:10.1016/S0140-6736(06)69204-0 PMID: 16905025

2. Royal College of Obstetricians and Gynaecologists. The Investigation and Treatment of Couples with Recurrent First-trimester and Second-trimester Miscarriage (Green-top Guideline No. 17). RCOG; 2011 (updated 2023). Available at: https://www.rcog.org.uk/guidance/browse-all-guidance/green-top-guidelines/

3. ESHRE Guideline Group on RPL, Bender Atik R, Christiansen OB, et al. ESHRE guideline: recurrent pregnancy loss. Hum Reprod Open. 2018;2018(2):hoy004. doi:10.1093/hropen/hoy004 PMID: 31486805

4. Brigham SA, Conlon C, Farquharson RG. A longitudinal study of pregnancy outcome following idiopathic recurrent miscarriage. Hum Reprod. 1999;14(11):2868-2871. doi:10.1093/humrep/14.11.2868 PMID: 10548385

5. Rai RS, Regan L, Clifford K, et al. Antiphospholipid antibodies and beta 2-glycoprotein-I in 500 women with recurrent miscarriage: results of a comprehensive screening approach. Hum Reprod. 1995;10(8):2001-2005. doi:10.1093/oxfordjournals.humrep.a136224 PMID: 8567829

6. Empson M, Lassere M, Craig J, Scott J. Prevention of recurrent miscarriage for women with antiphospholipid antibody or lupus anticoagulant. Cochrane Database Syst Rev. 2005;(2):CD002859. doi:10.1002/14651858.CD002859.pub2 PMID: 15846643 (Updated 2020)

7. Franssen MT, Korevaar JC, van der Veen F, et al. Reproductive outcome after chromosome analysis in couples with two or more miscarriages: case-control study. BMJ. 2006;332(7544):759-763. doi:10.1136/bmj.38735.459549.2F PMID: 16484237

8. Saravelos SH, Cocksedge KA, Li TC. Prevalence and diagnosis of congenital uterine anomalies in women with reproductive failure: a critical appraisal. Hum Reprod Update. 2008;14(5):415-429. doi:10.1093/humupd/dmn018 PMID: 18539641

9. Abalovich M, Amino N, Barbour LA, et al. Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2007;92(8 Suppl):S1-47. doi:10.1210/jc.2007-0141 PMID: 17948378

10. de Jong PG, Kaandorp S, Di Nisio M, Goddijn M, Middeldorp S. Aspirin and/or heparin for women with unexplained recurrent miscarriage with or without inherited thrombophilia. Cochrane Database Syst Rev. 2014;(7):CD004734. doi:10.1002/14651858.CD004734.pub4 PMID: 25048608 (ALIFE2 trial results published 2021)

11. Coomarasamy A, Devall AJ, Cheed V, et al. A randomized trial of progesterone in women with bleeding in early pregnancy (PRISM Trial). N Engl J Med. 2019;380(19):1815-1824. doi:10.1056/NEJMoa1813730 PMID: 31067371

12. National Institute for Health and Care Excellence. Ectopic Pregnancy and Miscarriage: Diagnosis and Initial Management (NICE Guideline NG126). NICE; 2019 (updated 2021). Available at: https://www.nice.org.uk/guidance/ng126

13. Liddell HS, Pattison NS, Zanderigo A. Recurrent miscarriage—outcome after supportive care in early pregnancy. Aust N Z J Obstet Gynaecol. 1991;31(4):320-322. doi:10.1111/j.1479-828x.1991.tb02811.x PMID: 1799343

14. Cumming GP, Klein S, Bolsover D, et al. The emotional burden of miscarriage for women and their partners: trajectories of anxiety and depression over 13 months. BJOG. 2007;114(9):1138-1145. doi:10.1111/j.1471-0528.2007.01452.x PMID: 17655731

15. Regan L, Braude PR, Trembath PL. Influence of past reproductive performance on risk of spontaneous abortion. BMJ. 1989;299(6698):541-545. doi:10.1136/bmj.299.6698.541 PMID: 2507063

16. Stephenson MD, Kutteh WH, Purkiss S, et al. Intravenous immunoglobulin and idiopathic secondary recurrent miscarriage: a multicentered randomized placebo-controlled trial. Hum Reprod. 2010;25(9):2203-2209. doi:10.1093/humrep/deq179 PMID: 20634187

17. de la Rochebrochard E, Thonneau P. Paternal age and maternal age are risk factors for miscarriage; results of a multicentre European study. Hum Reprod. 2002;17(6):1649-1656. doi:10.1093/humrep/17.6.1649 PMID: 12042293

18. Miyakis S, Lockshin MD, Atsumi T, et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost. 2006;4(2):295-306. doi:10.1111/j.1538-7836.2006.01753.x PMID: 16420554

19. Nouri K, Ott J, Huber JC, Fischer EM, Stögbauer L, Tempfer CB. Reproductive outcome after hysteroscopic septoplasty in patients with septate uterus—a retrospective cohort study and systematic review of the literature. Reprod Biol Endocrinol. 2010;8:52. doi:10.1186/1477-7827-8-52 PMID: 20492645

20. Coomarasamy A, Williams H, Truchanowicz E, et al. A randomized trial of progesterone in women with recurrent miscarriages (PROMISE Trial). N Engl J Med. 2015;373(22):2141-2148. doi:10.1056/NEJMoa1504927 PMID: 26605926

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