What are the key findings and management of a molar pregnancy?

Key Findings and Management of Molar Pregnancy

The primary treatment for molar pregnancy is suction dilation and curettage (D&C) under ultrasound guidance, followed by rigorous hCG monitoring to detect persistent gestational trophoblastic neoplasia. 1

Clinical Presentation

Molar pregnancy presents with distinctive clinical features:

• Vaginal bleeding: Most common presenting symptom (6-16 weeks gestation)
• Uterine enlargement: Particularly in complete molar pregnancy
• Markedly elevated hCG levels: Often >100,000 IU/L in complete moles, but less than 10% of partial moles show such elevations 2, 1
• Early-onset preeclampsia: Before 20 weeks gestation (rare but characteristic)
• Hyperemesis gravidarum: Severe nausea and vomiting
• Hyperthyroidism: Due to cross-reactivity of high hCG with thyroid-stimulating hormone receptors
• Theca lutein ovarian cysts: Causing bilateral ovarian enlargement 1

Types of Molar Pregnancy

Complete Molar Pregnancy

• No fetal parts (all chromosomal material derived from male)
• Marked uterine enlargement
• Very high hCG levels
• Classic "snowstorm" or "bunch of grapes" ultrasound appearance
• Hydropic/swollen chorionic villi creating vesicular pattern 1
• Higher risk of progression to gestational trophoblastic neoplasia (15-20%) 1

Partial Molar Pregnancy

• Triploid conceptus with abnormal fetus
• Smaller uterine size
• Lower hCG levels
• Ultrasound shows focal cystic spaces within placenta, empty/elongated gestational sac, or fetal anomalies
• Lower risk of progression to gestational trophoblastic neoplasia (1-5%) 1

Diagnostic Workup

The NCCN Panel recommends 2:

• History and physical examination
• Pelvic ultrasound (primary diagnostic tool)
• Quantitative hCG assay
• Complete blood count with platelets
• Liver, renal, and thyroid function tests
• Blood type and screen
• Chest X-ray

Definitive diagnosis requires histopathological examination of uterine contents, which is essential due to high false positive/negative rates of ultrasound, especially for partial molar pregnancy 1.

Management

Initial Treatment

1. Suction dilation and curettage (D&C) under ultrasound guidance to reduce risk of uterine perforation 2, 1
2. Rho(D) immunoglobulin administration for Rh-negative patients 2
3. Uterotonic agents (methylergonovine and/or prostaglandins) during and after procedure to reduce bleeding 2
4. Hysterectomy as alternative for women who do not wish to preserve fertility, older patients (>40 years), or cases with uncontrolled hemorrhage 2, 1

Prophylactic Chemotherapy

• May be considered for high-risk patients (age >40 years, hCG >100,000 mIU/mL, excessive uterine enlargement, theca lutein cysts >6 cm)
• Options include methotrexate or dactinomycin 2
• May reduce risk of progression to GTN by 3-8%, though evidence is not conclusive 2

Post-Evacuation Follow-up

• hCG monitoring every 1-2 weeks until levels normalize (3 consecutive normal assays)
• After normalization, hCG should be measured twice at 3-month intervals 2, 1
• Reliable contraception is mandatory during the entire monitoring period 1
• Extended monitoring (6 months) if normalization occurs after 56 days, as these patients have 3.8-fold higher risk of developing postmolar GTN 2

Postmolar Gestational Trophoblastic Neoplasia (GTN)

Diagnosed when any of the following criteria are met 2:

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

Treatment of Postmolar GTN

• Low-risk disease (FIGO score ≤6): Single-agent chemotherapy with methotrexate/folinic acid or actinomycin D
• High-risk disease (FIGO score ≥7): Multi-agent chemotherapy (EMA/CO regimen) 1
• Methotrexate is administered orally or intramuscularly in doses of 15-30 mg daily for a five-day course, repeated 3-5 times as required 3

Prognosis and Special Considerations

• With proper management and follow-up, cure rates approach 100% 1
• Fertility is generally preserved, with 83% of women becoming pregnant after chemotherapy 1
• Risk of recurrent molar pregnancy is 1-2% in subsequent pregnancies 4
• Twin pregnancy with molar component requires management in high-risk obstetric units, with 40-60% chance of a healthy baby 1

Common Pitfalls and Caveats

1. Early diagnosis: While early diagnosis by ultrasound has decreased medical complications, it has not reduced the incidence of postmolar GTN 4
2. Partial moles: Often misdiagnosed as incomplete or missed abortion due to similar presentation 5
3. Ectopic molar pregnancy: Rare but important to recognize as it carries similar malignancy potential as intrauterine molar pregnancy 6
4. Psychological impact: Considerable psychosocial repercussions require multidisciplinary support 4
5. Centralization of care: Referral to expert centers improves outcomes 1

The management of molar pregnancy has evolved significantly, with early diagnosis and standardized follow-up protocols leading to excellent outcomes. The key to success lies in proper initial evacuation followed by rigorous hCG monitoring to detect and treat persistent disease promptly.