What is the management and treatment of a molar pregnancy?

Management and Treatment of Molar Pregnancy

Initial Diagnosis and Workup

Molar pregnancy requires immediate suction dilation and curettage (D&C) under ultrasound guidance, followed by strict hCG surveillance to detect gestational trophoblastic neoplasia (GTN). 1

Diagnostic Assessment

Before evacuation, obtain the following workup:

• Quantitative serum hCG assay (typically markedly elevated beyond expected gestational age) 1, 2
• Pelvic ultrasound showing characteristic "snowstorm" appearance for complete mole or focal cystic spaces with possible fetal anomalies for partial mole 1, 2
• Complete blood count with platelets (assess for anemia from bleeding) 1
• Liver, renal, and thyroid function tests (hyperthyroidism can occur with very high hCG) 1, 3
• Blood type and screen (for Rh status and potential transfusion needs) 1
• Chest X-ray (baseline assessment for metastatic disease) 1, 2

Primary Treatment: Uterine Evacuation

Suction D&C under ultrasound guidance is the definitive treatment for all patients wishing to preserve fertility. 1, 2

Procedural Details

• Ensure blood availability pre-operatively due to hemorrhage risk 2
• Use ultrasound guidance throughout to ensure complete evacuation and avoid uterine perforation 1, 2
• Administer uterotonic agents (methylergonovine or prostaglandins) during and after the procedure to minimize bleeding 1
• Give Rho(D) immunoglobulin at evacuation for Rh-negative patients 1
• Never perform biopsy of suspected GTN lesions due to life-threatening hemorrhage risk 4, 2

Alternative for Completed Childbearing

Hysterectomy may be considered for patients who no longer desire fertility, as it reduces the risk of developing nonmetastatic GTN 3. However, this does not eliminate the need for hCG surveillance.

Post-Evacuation Surveillance Protocol

All patients require mandatory hCG monitoring regardless of mole type, as this is the most reliable method for early GTN detection. 1, 2

Monitoring Schedule

For Complete Hydatidiform Mole:

• hCG every 1-2 weeks until normalization (3 consecutive normal assays) 1, 2
• Monthly hCG for 6 months after normalization 1, 2

For Partial Hydatidiform Mole:

• hCG every 1-2 weeks until normalization 2
• One additional normal hCG measurement 1 month after initial normalization 2

Essential During Follow-Up

• Reliable contraception is mandatory throughout the entire monitoring period to maintain hCG reliability as a tumor marker 1, 5
• Hormonal contraception is specifically indicated to prevent pregnancy that would confound hCG interpretation 5

Diagnosis of Post-Molar GTN

Post-molar GTN is diagnosed when any of the following FIGO criteria are met: 4, 1

• hCG plateau for 4 consecutive values over 3 weeks 4, 1
• hCG rise >10% for 3 consecutive values over 2 weeks 4, 1
• hCG persistence 6 months or more after molar evacuation 4, 1

Risk Factors for GTN Development

Higher risk patients include those with:

• Age >40 years 1
• Pre-evacuation hCG >100,000 mIU/mL 1
• Excessive uterine enlargement 1
• Theca lutein cysts >6 cm 1

Note that complete moles progress to GTN in 15-20% of cases, while partial moles progress in only 1-5% 2, but both require identical surveillance protocols.

Management of Post-Molar GTN

Staging Workup When GTN Diagnosed

• Doppler pelvic ultrasound to confirm absence of pregnancy, measure uterine size, and assess tumor vasculature 4, 1
• Chest X-ray as initial metastatic screening 4, 1
• If chest X-ray positive: proceed with brain MRI and CT chest/abdomen/pelvis with contrast 1
• Repeat complete blood count, liver, renal, and thyroid function tests 4

Treatment Based on FIGO Prognostic Score

Low-Risk GTN (FIGO score 0-6):

• Single-agent chemotherapy with methotrexate or actinomycin D 4, 1

High-Risk GTN (FIGO score ≥7):

• Multi-agent chemotherapy regimens 1

Alternative to Chemotherapy

Repeat suction D&C or hysterectomy can be considered for persistent postmolar GTN confined to the uterus 4. In one observational study of 544 women, 68% required no further treatment after second curettage 4. However, chemotherapy was more likely needed when histologic trophoblastic disease was confirmed or urinary hCG exceeded 1,500 IU/L at second evacuation 4.

Critical Pitfalls to Avoid

• Never perform endometrial ablation in patients with history of molar pregnancy, as it masks GTN recurrence and is absolutely contraindicated 2, 6
• Do not biopsy visible genital tract lesions due to hemorrhage risk from fragile tumor vessels 4
• Avoid pregnancy during surveillance as it invalidates hCG monitoring and can occur even decades after molar pregnancy 6
• Do not skip surveillance even if pathology shows partial mole, as GTN still develops in 1-5% 2
• Consider phantom hCG if hCG elevated with no imaging evidence of disease 4

Long-Term Outcomes and Counseling

Reproductive outcomes after molar pregnancy are comparable to the general population 5, with the exception of:

• Recurrent molar pregnancy risk of 1-2% in subsequent pregnancies 5
• Patients with recurrent complete moles may have familial recurrent hydatidiform mole (FRHM), an autosomal recessive condition requiring genetic counseling and potentially ovum donation for future pregnancy 4, 2

Cure rates for GTN are excellent with appropriate treatment 7, but all patients should receive psychologic support given the considerable psychosocial impact of this diagnosis 5, 7.