A complete mole in the first trimester is often only an enlarged cavity with cystic placental change and very high hCG; a partial mole has a fetus with a focally cystic placenta — imaging suggests, histology confirms, and hCG follow-up detects persistent disease.
Orient first
- The classic snowstorm pattern is a second-trimester sign; early moles are subtle and often diagnosed as missed miscarriage.
- Theca lutein cysts in the ovaries accompany high hCG.
- Persistent trophoblastic disease: myometrial invasion with hypervascularity on colour Doppler.
Acquire the study
- Transvaginal and transabdominal ultrasound with colour Doppler.
The manoeuvre
- Cavity: heterogeneous mass with multiple small cystic spaces; measure in cm.
- Fetus: absent (complete) vs present, often abnormal (partial) — measure CRL in mm.
- Placenta in partial mole: focal cystic change, increased thickness.
- Colour Doppler of the myometrium: hypervascular invasion suggests invasive mole.
- Ovaries: bilateral multiloculated theca lutein cysts.
What confirms it
- Histology of evacuated tissue.
What licenses you to exclude it
- A normal ultrasound does not exclude early molar pregnancy; histology of all failed pregnancies is recommended in many guidelines (verify).
The classic misread
- Calling hydropic degeneration of a missed miscarriage a mole.