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Gestational trophoblastic disease (molar pregnancy)
A complete mole is a purely paternal pregnancy without a fetus and with a very high hCG; it is treated by suction evacuation and hCG is followed until it disappears, because a rise or plateau in hCG indicates trophoblastic neoplasia, which responds very well to chemotherapy.
Why it matters in the exam
The classic exam picture: first-trimester bleeding, a uterus larger than expected, a very high hCG, severe vomiting, preeclampsia before 20 weeks or hyperthyroidism, and a "snowstorm" on ultrasound without a fetus. You must separate a complete mole (46,XX of purely paternal origin, no fetal tissue, p57 negative) from a partial mole (triploid 69,XXY, fetal parts present, p57 positive, a much lower risk of malignant change).
Treatment is suction evacuation of the uterus, even when the uterus is large, and anti-D for an Rh-negative woman; hysterectomy is an option for a woman who has finished childbearing. After evacuation hCG is followed weekly until three negative results, then monthly, with reliable contraception (the pill is allowed). Trophoblastic neoplasia is diagnosed by a plateau of hCG over four measurements across 3 weeks, a rise of 10% or more over three measurements across two weeks, hCG still positive at 6 months, or a histological diagnosis of choriocarcinoma. The most common metastases are to the lungs, so a chest X-ray is done. At low risk (score 0–6) — methotrexate or actinomycin D; at high risk (7 or more) — combination chemotherapy. Choriocarcinoma can follow any pregnancy, even a normal birth.
Key points
- Complete mole: 46,XX paternal, no fetus, very high hCG; partial mole: 69,XXY with fetal parts.
- Treatment: suction evacuation and anti-D as needed.
- Follow hCG to negative, with reliable contraception.
- GTN: plateau or rise in hCG; chest X-ray.
- Low risk → methotrexate; high risk → combination chemotherapy.
Summary table
| Condition | Features | Work-up | Treatment |
|---|---|---|---|
| Complete mole | 46,XX paternal, no fetus, very high hCG, snowstorm, p57 negative | Ultrasound, hCG, TSH, blood pressure | Suction evacuation; hCG follow-up; 15%–20% risk of neoplasia |
| Partial mole | 69,XXY, fetal parts, p57 positive | Ultrasound and pathology | Suction evacuation; shorter hCG follow-up; low risk of neoplasia |
| Follow-up after evacuation | Weekly hCG until 3 negative results, then monthly | — | Reliable contraception; the pill is allowed |
| Trophoblastic neoplasia (GTN) | Plateau over 4 measurements across 3 weeks, a 10% rise over three measurements across two weeks, or hCG positive at 6 months | Chest X-ray, imaging, risk score | Low risk (0–6): methotrexate; high risk (7 or more): combination chemotherapy |
| Choriocarcinoma | After any pregnancy; metastases to lungs and brain | hCG, imaging | Chemotherapy; high cure rate |
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Sources
- ACOG Practice Bulletin No. 53, 2004, reaffirmed — Diagnosis and Treatment of Gestational Trophoblastic Disease
- FIGO Cancer Report, 2021 — Update on the diagnosis and management of gestational trophoblastic disease
- NCCN Guidelines: Gestational Trophoblastic Neoplasia, 2024 — Hydatidiform mole and GTN
- Berek and Novak's Gynecology, 16th edition (2019) — Gestational Trophoblastic Disease
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.