Treatment of Molar Pregnancy
Suction dilation and curettage, preferably under ultrasound guidance, is the primary treatment for hydatidiform mole, followed by serial hCG monitoring every 1-2 weeks until normalization, then monthly for up to 6 months depending on mole type. 1, 2
Immediate Management at Diagnosis
Pre-Evacuation Workup
- Obtain baseline serum hCG level, complete blood count, liver/renal/thyroid function tests (thyroid particularly important if clinical suspicion of hyperthyroidism exists) 1, 2
- Perform chest X-ray to assess for metastatic disease or establish baseline 1, 2
- Confirm blood group and crossmatch blood products, as transfusion may be urgently needed 1
- Perform pelvic ultrasound to confirm diagnosis and assess uterine size 1, 2
Surgical Evacuation Procedure
- Perform suction curettage under anesthesia as soon as possible after diagnosis 1, 2, 3
- Ultrasound guidance during the procedure reduces perforation risk 1, 2
- Administer uterotonic agents (methylergonovine and/or prostaglandins) during and for several hours after the procedure to reduce bleeding 2
- Consider cervical ripening agents before evacuation 1
- Administer Rho(D) immunoglobulin to all Rh-negative patients at time of evacuation 1, 2
- Send tissue for histopathologic examination (required for definitive diagnosis) and consider fresh tissue for genetic analysis 1, 4
Alternative to Suction Curettage
- Hysterectomy is an option for women who have completed childbearing and wish to eliminate the risk of postmolar gestational trophoblastic neoplasia (GTN) 2, 5
- This reduces but does not eliminate the need for hCG monitoring 5
Post-Evacuation hCG Monitoring Protocol
Initial Monitoring Phase
- Measure serum hCG at least every 1-2 weeks until normalization (undetectable level) 1, 2, 4
- Use the same laboratory and assay type for all serial measurements to ensure consistency 2
- Continue weekly measurements until two consecutive undetectable values are obtained 4
Extended Monitoring Based on Mole Type
For Complete Hydatidiform Mole (CHM):
- After hCG normalizes, continue monthly monitoring for up to 6 months 1, 2, 4
- If hCG becomes undetectable within 56 days after evacuation, only four additional monthly measurements are required 4
- If hCG normalizes after 56 days, monthly monitoring for 6 months is mandatory 4
For Partial Hydatidiform Mole (PHM):
- After hCG normalizes, obtain one additional normal hCG value before discharge from monitoring 1, 2, 4
- This typically requires only one month of post-normalization monitoring 1
Contraception During Monitoring
- Recommend reliable contraception throughout the entire monitoring period 4
- Pregnancy during monitoring makes hCG interpretation impossible and delays detection of GTN 4
Indications for Chemotherapy (Postmolar GTN)
FIGO Diagnostic Criteria for GTN
Chemotherapy is indicated when any of the following occur 1:
- hCG plateau: Four consecutive values over at least 3 weeks (days 1,7,14,21) showing <10% change 1
- hCG rise: Two consecutive rises of ≥10% over at least 2 weeks (days 1,7,14) 1
- Persistent elevation: hCG remains detectable 6 months or more after evacuation 1
Additional High-Risk Indications
- Heavy vaginal bleeding requiring transfusion despite falling hCG 1
- Histological evidence of choriocarcinoma on pathology 1
- Metastases to brain, liver, or gastrointestinal tract 1
- Lung metastases >2 cm on chest X-ray 1
- Serum hCG ≥20,000 IU/L more than 4 weeks after evacuation (associated with increased uterine perforation risk) 1
Important Exception to the 6-Month Rule
Recent high-quality evidence demonstrates that chemotherapy is NOT automatically required for patients with low, declining hCG at 6 months post-evacuation. 6, 7
- In a UK study of 66 patients with hCG still detectable at 6 months who continued surveillance, 98% achieved spontaneous remission without chemotherapy 6
- A Brazilian multicenter study showed 80% of expectantly managed patients achieved spontaneous remission 7
- Continue surveillance rather than initiating chemotherapy if hCG is low (<100 IU/L) and declining at 6 months 6, 7
- Median hCG of 13 IU/L at 6 months was associated with excellent outcomes under surveillance 6
Prophylactic Chemotherapy Considerations
High-Risk Criteria for Prophylactic Treatment
Prophylactic methotrexate or dactinomycin may be considered for 2:
- Age >40 years
- hCG levels >100,000 mIU/mL at diagnosis
- Excessive uterine enlargement
- Theca lutein cysts >6 cm
Evidence and Limitations
- Prophylactic chemotherapy reduces postmolar GTN incidence by only 3-8% 2
- This exposes many women unnecessarily to chemotherapy toxicity 2
- Most guidelines do not routinely recommend prophylactic chemotherapy given the small absolute benefit 1, 2
Staging Investigations When GTN Develops
For Postmolar GTN (Most Common Scenario)
- Pelvic Doppler ultrasound to assess uterine disease extent and vascularity 1
- Chest X-ray (CT chest only if CXR shows lesions) 1
- If chest X-ray shows metastases, obtain MRI brain and CT abdomen to exclude brain/liver involvement 1
FIGO Risk Scoring
Calculate FIGO 2000 prognostic score to determine treatment intensity 1:
- Score 0-6 (low-risk): Single-agent chemotherapy with methotrexate or actinomycin D
- Score ≥7 (high-risk): Multi-agent combination chemotherapy required
Critical Pitfalls to Avoid
- Never use medical evacuation (misoprostol alone) for suspected molar pregnancy 4
- Never initiate chemotherapy based solely on elevated hCG without histologic confirmation and exclusion of normal pregnancy 2
- Do not perform repeat curettage for postmolar GTN - remission rate is low (68%) and perforation risk is significant 1, 2
- Do not automatically treat patients with low, declining hCG at 6 months - surveillance is appropriate 6, 7
- Ensure ultrasound or hysteroscopy confirms complete evacuation to avoid misdiagnosing retained products as GTN 1