Miscarriage
Exam Tips
- In OSCEs, first prioritise red flags (shock, severe pain, heavy bleeding, sepsis) and same-day EPAU/gynaecology referral pathways.
- Always exclude ectopic pregnancy before confirming miscarriage management plans.
- Classify by stage (threatened/inevitable/missed/incomplete/complete) because this directs treatment and counselling.
- Know UK viability cut-off (24 weeks) and recurrent miscarriage definition (>=3 losses in UK practice).
- Use empathetic language and safety-netting as scored communication domains in clinical exams.
- Ultrasound pattern recognition is high yield; see figure sets for first-trimester non-viable pregnancy and retained products in standard obstetrics texts (for example Danforth's Obstetrics and Gynecology, Early Pregnancy Loss chapter).
Definition
Miscarriage is the spontaneous loss of an intrauterine pregnancy before fetal viability, conventionally before 24+0 weeks in UK practice. It includes early loss (<13 weeks) and late loss (13-24 weeks), and clinically presents as threatened, inevitable, missed, incomplete, or complete miscarriage.
Pathophysiology
Most first-trimester miscarriages result from embryonic/fetal chromosomal abnormalities (commonly aneuploidy), leading to failed embryogenesis and trophoblastic dysfunction. This causes declining progesterone support, decidual breakdown, uterine bleeding, prostaglandin-mediated uterine contractions, and eventual cervical dilatation with expulsion of products of conception; in missed miscarriage, fetal demise occurs but retained tissue delays expulsion. In recurrent miscarriage, mechanisms are more heterogeneous (parental chromosomal rearrangements, antiphospholipid syndrome, uterine anomaly, endocrine/metabolic and immune factors), and many cases remain unexplained.
Risk Factors
- Advanced maternal age (strongest epidemiological risk; marked rise after age 35, very high by age 45+)
- Previous miscarriage (risk increases with number of prior losses)
- Fetal/parental chromosomal abnormalities (including balanced translocations)
- Antiphospholipid syndrome and selected thrombophilias
- Congenital uterine anomalies (for example septate or bicornuate uterus)
- Endocrine/metabolic disease (poorly controlled diabetes, thyroid disease, PCOS)
- Lifestyle/environmental factors (smoking, higher alcohol intake, excess caffeine, obesity, pollutant exposure)
- Advanced paternal age
- Black African or Black Caribbean ethnicity (higher observed odds in UK cohort data)
- Vitamin D deficiency (association reported, causality/intervention benefit uncertain)
Clinical Features
Symptoms
- Vaginal bleeding in early pregnancy (spotting to heavy bleeding with clots/tissue)
- Lower abdominal or suprapubic cramping pain
- Passage of products of conception
- Reduction/loss of pregnancy symptoms (for example nausea, breast tenderness), especially in missed miscarriage
- Dizziness/syncope if significant blood loss
Signs
- Haemodynamic compromise in severe cases (tachycardia, hypotension, pallor, shock/collapse)
- Abdominal, pelvic, or cervical motion tenderness
- Open cervical os in inevitable/incomplete miscarriage; closed os often seen in threatened/missed miscarriage
- Active vaginal bleeding; retained tissue at or through cervical os
- Fever, uterine tenderness, offensive discharge if septic miscarriage
Investigations
Management
Lifestyle Modifications
- Provide clear safety-net advice: urgent review for heavy bleeding (for example soaking >=2 pads/hour for >=2 hours), severe unilateral pain, syncope, fever, or offensive discharge.
- Offer empathetic counselling and bereavement support for patient and partner; acknowledge risk of anxiety/depression after loss.
- Expectant management is appropriate in selected stable patients (especially very early bleeding without pain), with repeat pregnancy testing/scan follow-up through EPAU.
- Advise optimisation of future pregnancy health: smoking cessation, reduce alcohol/caffeine, weight and glycaemic/thyroid control, folic acid 400 micrograms daily pre-conception to 12 weeks (5 mg if high-risk indications).
Pharmacological Treatment
Medical management of missed/incomplete miscarriage (prostaglandin +/- antiprogesterone)
- Mifepristone 200 mg orally once, followed 24-48 hours later by misoprostol 800 micrograms vaginal/buccal/oral
- If mifepristone not used: misoprostol 800 micrograms vaginal/buccal/oral (single dose, with local protocol for repeat dosing if needed)
Use only after excluding ectopic pregnancy and in haemodynamically stable patients. Contraindications/cautions: suspected ectopic pregnancy, severe sepsis/haemorrhage needing urgent surgery, chronic adrenal failure, inherited porphyria, and severe uncontrolled asthma on systemic corticosteroids (mifepristone caution). Warn about heavy bleeding, pain, and need for emergency care if excessive bleeding or collapse.
Analgesia
- Paracetamol 1 g orally every 4-6 hours (max 4 g/day)
- Ibuprofen 400 mg orally three times daily with food if no contraindication
Avoid NSAIDs in renal impairment, peptic ulcer disease, NSAID hypersensitivity, or high GI bleed risk. Escalate analgesia and reassess if pain is disproportionate (consider ectopic or sepsis).
Anti-D prophylaxis (RhD-negative, unsensitised patients when indicated)
- Anti-D immunoglobulin 250 IU IM up to 19+6 weeks
- Anti-D immunoglobulin 500 IU IM from 20+0 weeks
Give as soon as possible (ideally within 72 hours) after sensitising event or relevant management, according to local obstetric protocol.
Septic miscarriage (empiric IV antibiotics, then tailor)
- Co-amoxiclav 1.2 g IV every 8 hours plus metronidazole 500 mg IV every 8 hours
- If severe penicillin allergy: clindamycin 600-900 mg IV every 8 hours plus gentamicin (weight-based once daily)
Start promptly with sepsis bundle and urgent senior obstetric/gynaecology input; adjust to cultures and renal function.
Surgical / Interventional
- Surgical uterine evacuation (manual vacuum aspiration or suction curettage) for haemodynamic instability, heavy/persistent bleeding, sepsis, retained products with ongoing symptoms, or patient preference.
- Immediate resuscitation (ABC approach, IV access, crystalloids, blood products as needed) when unstable.
- Send products of conception for histology/genetic testing when clinically indicated (for example recurrent miscarriage, uncertain diagnosis, concern about molar pregnancy).
Complications
- Psychological morbidity (anxiety, depressive symptoms, grief reaction, and potential post-traumatic stress symptoms)
- Haemorrhage and anaemia
- Retained products of conception causing persistent bleeding/pain
- Infection and sepsis (including septic miscarriage)
- Procedure-related cervical/uterine trauma (including perforation) during evacuation
- Intrauterine adhesions (Asherman syndrome, rare) after curettage
- Recurrent miscarriage risk in future pregnancies
Prognosis
Overall prognosis is favourable: many people will achieve a subsequent live birth, including a substantial proportion with unexplained recurrent miscarriage when supported in dedicated early pregnancy services. Prognosis is influenced by maternal age, number of previous miscarriages, and modifiable comorbidity (for example diabetes/thyroid control).
Sources & References
🏥BMJ Best Practice(2)
✅NICE Guidelines(1)
- Miscarriage[overview]
📖Textbook References(1)
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1695, 1696)[context]