A molar pregnancy is a tumor due to the uncontrolled proliferation of trophoblasts, which are cells that surround the blastocyst and later become the placenta. These “moles” are categorized into complete and partial.
| Complete moles | Partial moles |
| No fetal/embryonic tissue | May contain fetal structures, albeit abnormal ones |
| Abnormally elevated B-hCG levels: >100,000 mIU/mL | Normal B-hCG levels |
Presentation:
- Vaginal bleeding
- Exaggerated uterine size for gestational age
- Hyperemesis
- Pregnancy-induced hypertension
A molar pregnancy will appear on ultrasound as a “snowstorm” inside the uterus. The contents of the uterus are complex and heterogeneous and often contain many small cystic structures. In addition, there may be theca-lutein cysts in the ovaries which are thin-walled cystic structures (these are more common in 2nd-trimester complete moles).
