Reproductive · Gestational Trophoblastic Disease
The facts most likely to be tested
Complete moles are characterized by a 46,XX diploid karyotype resulting from dispermic fertilization of an empty ovum, lacking all fetal tissue.
Partial moles are characterized by a 69,XXY triploid karyotype resulting from fertilization of a normal ovum by two sperm, often containing fetal parts.
Patients typically present with vaginal bleeding, a uterus that is larger than expected for gestational age, and hyperemesis gravidarum.
Serum beta-hCG levels in hydatidiform moles are markedly elevated and disproportionate to the gestational age.
Transvaginal ultrasound classically reveals a snowstorm appearance or cluster of grapes pattern representing hydropic villi.
The definitive treatment for a hydatidiform mole is suction curettage followed by serial monitoring of beta-hCG levels to ensure they return to zero.
Persistent or rising beta-hCG levels following evacuation are diagnostic of gestational trophoblastic neoplasia, necessitating evaluation for choriocarcinoma.
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A 24-year-old G1P0 woman at 12 weeks gestation presents to the clinic with vaginal spotting and severe nausea. On physical examination, the fundal height is 18 cm, which is greater than expected for her dates. A pelvic ultrasound demonstrates a heterogeneous uterine mass with multiple small cystic spaces, described as a snowstorm pattern, and no fetal heart tones are identified. Her serum beta-hCG is 150,000 mIU/mL.
What is the most appropriate next step in management?
Suction curettage
The clinical presentation of a uterus larger than dates, markedly elevated beta-hCG, and the classic 'snowstorm' ultrasound finding is diagnostic of a hydatidiform mole, which requires immediate uterine evacuation via suction curettage.
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Etiology / Epidemiology
Results from abnormal fertilization. Advanced maternal age and prior molar pregnancy are primary risk factors.
Clinical Manifestations
Presents with painless vaginal bleeding and uterine size > dates. Hyperemesis gravidarum is common.
Diagnosis
Transvaginal ultrasound reveals a snowstorm pattern. Markedly elevated β-hCG is diagnostic.
Treatment
Suction curettage is the definitive management. Avoid oxytocin prior to evacuation.
Prognosis
Risk of gestational trophoblastic neoplasia requires serial β-hCG monitoring until undetectable.
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Epidemiology & Etiology
Incidence is highest in Asian populations and extremes of maternal age (<20 or >35). A prior molar pregnancy increases recurrence risk to 1-2%. It represents a spectrum of gestational trophoblastic disease.
Pertinent Anatomy
The pathology involves the chorionic villi of the placenta. The uterus becomes distended by fluid-filled vesicles, often exceeding the expected size for gestational age.
Pathophysiology
Complete moles are typically 46,XX (diploid) from paternal origin, while partial moles are triploid (69,XXX or XXY). Excessive trophoblastic proliferation leads to massive production of β-hCG. This hormonal surge causes theca lutein cysts and systemic symptoms.
Clinical Manifestations
Patients present with painless vaginal bleeding in the first trimester. Physical exam shows uterine size > dates and grape-like vesicles passing through the cervix. Preeclampsia before 20 weeks is a classic red flag for molar pregnancy.
Diagnosis
Transvaginal ultrasound is the gold standard, showing a snowstorm or cluster of grapes appearance. β-hCG levels are typically >100,000 mIU/mL, significantly higher than normal pregnancy.
Treatment
Suction curettage is the first-line treatment to evacuate the uterus. Avoid oxytocin before evacuation to prevent embolization of trophoblastic tissue. If the patient has completed childbearing, hysterectomy is an alternative.
Prognosis
Patients require weekly β-hCG levels until they reach zero, then monthly for 6 months. Gestational trophoblastic neoplasia occurs in 15-20% of complete moles, requiring chemotherapy with methotrexate.
Differential Diagnosis
Multiple gestation: confirmed by ultrasound showing multiple fetuses
Threatened abortion: β-hCG levels correlate with gestational age
Ectopic pregnancy: adnexal mass with lower β-hCG rise
Hyperemesis gravidarum: lacks the uterine size discrepancy
Choriocarcinoma: malignant progression with metastatic potential