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Molar Pregnancy
Gestational Trophoblastic Disease
Gestational trophoblastic disease (GTD) is a spectrum of disorders caused by abnormal proliferation of placental trophoblast. It includes:
- Hydatidiform mole–complete or partial (non-invasive)
- Invasive mole
- Choriocarcinoma
- Placental-site and epithelioid trophoblastic tumours
Invasive mole, choriocarcinoma and placental-site/epithelioid tumours are grouped as gestational trophoblastic neoplasia (GTN); cure rates exceed 90 % with modern chemotherapy.
Incidence
- Worldwide: 0.2–2 / 1 000 pregnancies (higher in Asia and Africa).
- South Africa: ≈ 1.2 / 1 000 deliveries.
- Post-molar GTN develops in ≈ 20 % of complete and 4 % of partial moles.
Placental Trophoblast
- Cytotrophoblast–proliferative stem cells
- Intermediate trophoblast–invasive phenotype
- Syncytiotrophoblast–secretes human chorionic gonadotrophin (hCG)
Hydropic villous swelling with trophoblastic hyperplasia produces the classical “grape-like” vesicles.
Risk Factors
- Maternal age < 20 yr or > 35 yr
- Previous miscarriage or molar pregnancy (1–2 % recurrence)
- Asian or African ancestry
- Diet deficient in vitamin A, folate or protein
Hyperthyroidism
hCG shares an α-subunit with thyroid-stimulating hormone (TSH); high hCG concentrations and a more thyrotropic isoform lead to thyroid stimulation.
- Biochemical hyperthyroidism: up to 20 %
- Clinical thyrotoxicosis: 5–10 %
- Risk of thyroid storm around evacuation
Clinical Features (often Present in 1st–2nd trimester)
- Irregular vaginal bleeding ± anaemia
- Uterine size > dates
- Hyperemesis gravidarum
- Pre-eclampsia before 20 weeks
- Theca lutein ovarian cysts
- Passage of vesicles
- Signs of hyperthyroidism or high-output cardiac failure
- Respiratory distress from trophoblastic emboli or pulmonary metastases
Diagnosis
| Investigation | Findings |
|---|---|
| Ultrasound | “Snow-storm” pattern (complete); cystic spaces with fetal tissue (partial) |
| β-hCG | Markedly elevated; plateau or rise after evacuation suggests GTN |
| Histology | Confirms mole and classifies GTD |
Management of the Mole
- Evacuation: ultrasound-guided suction dilatation & curettage (D&C) with oxytocin after uterine evacuation to minimise trophoblastic embolisation.
- Anti-D immunoglobulin for Rh-negative patients.
- Hysterectomy if family complete or uncontrollable haemorrhage.
- Follow-up: serum β-hCG weekly until normal, then monthly for 6 months (longer if high-risk). Effective contraception is essential.
- Chemotherapy (methotrexate or actinomycin D ± multi-agent regimens) for GTN based on FIGO risk score.
Anaesthesia for Evacuation or Hysterectomy
Pre-operative Assessment
- Full history with focus on thyroid, cardiovascular and pre-eclampsia symptoms.
- Investigations:
- FBC, U&E, LFT, coagulation profile, blood group & cross-match
- Thyroid hormones (FT₄, TSH)
- Baseline β-hCG
- ECG ± transthoracic echo if cardiac compromise
- Chest X-ray if respiratory symptoms/metastatic disease
- Optimise:
- Volume status and anaemia
- Pre-eclampsia–magnesium sulphate if indicated
- Hyperthyroidism–propylthiouracil or carbimazole, β-blockade (e.g. propranolol or esmolol), iodide if surgery cannot wait, hydrocortisone 100 mg IV to block T₄→T₃ conversion in emergencies.
Intra-operative Considerations
| Aspect | Recommendations |
|---|---|
| Monitoring | Standard ASA ± arterial line, large-bore IV; central line if haemodynamically unstable |
| Anaesthetic technique | • Spinal/epidural safe in haemodynamically stable patients–allows early recognition of thyroid or cardiovascular decompensation • General anaesthesia (GA) preferred if severe bleeding, airway concerns, or thyroid storm risk |
| Induction | Propofol 2–2.5 mg kg⁻¹; etomidate if unstable; avoid ketamine (sympathomimetic) |
| Maintenance | Volatile agent with air/O₂ ± remifentanil; MAC unchanged but minimise uterine relaxation |
| Uterotonics | Start oxytocin infusion after suction commences or once uterus empty; avoid ergometrine until blood pressure stable |
| β-blocker | Esmolol infusion (e.g. 50–200 µg kg⁻¹ min⁻¹) blunts hyperadrenergic response and may reduce blood loss |
| Ventilation | Low tidal volume/high FiO₂ if risk of trophoblastic emboli or pulmonary oedema |
Post-operative Care
- High-care or ICU observation for haemorrhage, cardiopulmonary compromise and thyroid storm.
- Continue β-blocker and anti-thyroid therapy until β-hCG normalises and thyroid function stabilises.
- Early involvement of GTD centre for ongoing surveillance.
Peri-operative Complications to Anticipate
- Massive uterine bleeding → DIC
- Thyroid storm (hyperthermia, tachyarrhythmia, heart failure)
- Pulmonary trophoblastic embolism or metastases
- Pre-eclampsia/eclampsia
- Acute cardiomyopathy or high-output failure
Differential Diagnosis of Hyperthyroidism in Pregnancy
| Primary thyroid disease | Gestational causes | Other causes |
|---|---|---|
| Graves’ disease, toxic adenoma, toxic multinodular goitre, thyroiditis | Transient gestational thyrotoxicosis, multiple gestation, molar pregnancy, TSH-receptor mutation, hyperplacentosis, hyperreactio luteinalis | Iatrogenic (exogenous thyroxine), struma ovarii, TSH-secreting pituitary adenoma |
Links
- Obstetric emergencies
- Maternal conditions
- Gynaecological Surgery
- Non obstetric surgery
- Fetus and Placenta
- Maternal collapse and CPR
- Endocrine and Metabolic
References:
- Swaminathan S, James RA, Chandran R, Joshi R. Anaesthetic Implications of Severe Hyperthyroidism Secondary to Molar Pregnancy: A Case Report and Review of Literature. Anesth Essays Res. 2017 Oct-Dec;11(4):1115-1117. doi: 10.4103/aer.AER_38_17. PMID: 29284889; PMCID: PMC5735464.
- Tidy J, Seckl M, Hancock BW. Management of Gestational Trophoblastic Disease. Green-top Guideline No. 38. BJOG. 2021;128:e1–e27. tjodistanbul.org
- Badlaeva A, et al. Hyperthyroidism Associated with Gestational Trophoblastic Neoplasia: Systematic Literature Review and Pathways Analysis. Cancers. 2025;17:1398. mdpi.com
- Hydatidiform Mole. StatPearls [Internet]. Updated 2025. ncbi.nlm.nih.gov
- NHS Scotland. Gestational Trophoblastic Disease (Molar Pregnancy) Guideline. 2023. rightdecisions.scot.nhs.uk
- Hydatidiform Mole–Treatment & Management. Medscape Reference. Updated 2024. emedicine.medscape.com
Summaries:
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