Complete Hydatidiform Mole vs. Partial Hydatidiform Mole

What's the Difference?

Complete Hydatidiform Mole and Partial Hydatidiform Mole are both types of gestational trophoblastic disease that occur during pregnancy. However, they differ in their characteristics and outcomes. Complete Hydatidiform Mole is a nonviable pregnancy where the placenta develops abnormally and forms a mass of cysts, while Partial Hydatidiform Mole is a rare condition where there is a mix of normal and abnormal placental tissue. Complete Hydatidiform Mole is associated with a higher risk of complications such as choriocarcinoma, whereas Partial Hydatidiform Mole has a lower risk of complications and a better prognosis. Treatment for both conditions typically involves surgical removal of the abnormal tissue.


AttributeComplete Hydatidiform MolePartial Hydatidiform Mole
Genetic Makeup46XX69XXY or 69XXX
Embryonic TissueNoneSome embryonic tissue present
Chorionic VilliSwollen and hydropicSwollen and hydropic
Risk of Persistent Gestational Trophoblastic DiseaseHighLow

Further Detail


Hydatidiform moles are abnormal growths that occur in the uterus during pregnancy. There are two main types of hydatidiform moles: complete hydatidiform mole (CHM) and partial hydatidiform mole (PHM). While both types are considered gestational trophoblastic diseases, they have distinct characteristics that differentiate them from each other.

Genetic Makeup

One of the key differences between CHM and PHM lies in their genetic makeup. CHM is characterized by the absence of fetal tissue, with all genetic material coming from the father. This results in a complete mole with no identifiable fetal parts. In contrast, PHM contains both maternal and paternal genetic material, leading to the presence of some fetal tissue alongside abnormal trophoblastic tissue.

Clinical Presentation

When it comes to clinical presentation, CHM and PHM also exhibit differences. CHM often presents with symptoms such as vaginal bleeding, enlarged uterus, and elevated levels of beta-human chorionic gonadotropin (β-hCG). On the other hand, PHM may present with similar symptoms but is more likely to have a triploid karyotype and less elevated levels of β-hCG compared to CHM.

Ultrasound Findings

Ultrasound imaging plays a crucial role in the diagnosis of hydatidiform moles. CHM typically appears as a snowstorm pattern on ultrasound, characterized by multiple small cystic spaces within a thickened endometrium. In contrast, PHM may show a partial mole pattern on ultrasound, with some evidence of fetal parts alongside abnormal placental tissue.

Risk of Gestational Trophoblastic Neoplasia

One important consideration when dealing with hydatidiform moles is the risk of developing gestational trophoblastic neoplasia (GTN). CHM has a higher risk of progressing to GTN compared to PHM. Therefore, patients with CHM may require closer monitoring and follow-up to detect any signs of malignant transformation early on.

Treatment Approach

The management of CHM and PHM also differs based on their distinct characteristics. CHM is typically treated with suction dilation and curettage (D&C) to remove the abnormal tissue from the uterus. In contrast, PHM may require a more conservative approach, as there is a possibility of preserving some fetal tissue. Close monitoring with serial β-hCG levels and ultrasound may be sufficient in some cases of PHM.


Overall, the prognosis for patients with CHM and PHM is generally good, especially with early detection and appropriate management. Most cases of hydatidiform moles resolve without complications, and fertility can be preserved in many instances. However, the risk of GTN should always be considered, especially in cases of CHM, which have a higher likelihood of malignant transformation.

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