{
    "abstract": "A hydatidiform mole, commonly referred to as a molar pregnancy, is a rare abnormality in pregnancy classified under gestational trophoblastic diseases (GTD), which stem from the placenta and may metastasize.\u00a0Hydatidiform moles are characterized by abnormal fertilization, resulting in villous hydrops and trophoblastic hyperplasia with or without embryonic development.\u00a0Other forms of GTD include gestational choriocarcinoma\u2014which can be aggressively\u00a0malignant and invasive\u2014and placental site trophoblastic tumors. Please see StatPearls' companion reference, \"Gestational Trophoblastic Disease,\" for more information.\u00a0Although described as early as Hippocrates\u2019 era, who explained their formation through the consumption of dirty water by pregnant women, the condition was more accurately characterized in 1752 by William Smelie, who likened its appearance to a \u201cbunch of grapes,\u201d a hallmark feature of molar pregnancies resulting from swollen, hydropic villi. Hydatidiform moles are categorized as complete or partial and are usually noninvasive forms of GTD. Overrepresentation of the paternal genome in sporadic hydatidiform moles is a fundamental genetic event leading to overall alteration of imprinting gene expression in the molar trophoblast,\u00a0being completely\u00a0androgenetic in complete hydatidiform moles and diandric triploid in partial hydatidiform moles.\u00a0However, although\u00a0hydatidiform moles are considered benign, they are premalignant lesions and can potentially become malignant and invasive.\u00a0 Complete molar pregnancies present with symptoms such as first-trimester vaginal bleeding, severe nausea, and high \u03b2-human chorionic gonadotropin (\u03b2-hCG) levels. Partial moles may present similarly but often resemble a spontaneous abortion and may include detectable fetal heart tones. Both molar types are detectable via ultrasonography, which\u00a0typically reveals distinct patterns; complete moles demonstrate anechoic cystic clusters (\u201cgrape clusters\u201d) and partial moles demonstrate fetal parts. Histopathological examination postevacuation confirms the diagnosis\u00a0with visualization of characteristic villous changes. Treatment typically involves dilation and curettage (D&C), and hysterectomy may be considered for patients not desiring future pregnancies. Posttreatment, regular \u03b2-hCG monitoring is essential to detect potential progression to gestational trophoblastic neoplasia (GTN).",
    "authors": [
        {
            "collective": null,
            "firstname": "Lauren",
            "initials": "L",
            "lastname": "Cue"
        },
        {
            "collective": null,
            "firstname": "Fabiola",
            "initials": "F",
            "lastname": "Farci"
        },
        {
            "collective": null,
            "firstname": "Sassan",
            "initials": "S",
            "lastname": "Ghassemzadeh"
        },
        {
            "collective": null,
            "firstname": "Michael",
            "initials": "M",
            "lastname": "Kang"
        }
    ],
    "copyrights": "Copyright \u00a9 2025, StatPearls Publishing LLC.",
    "doi": null,
    "isbn": null,
    "language": "eng",
    "publication_date": "2025",
    "publication_type": "Study Guide",
    "publisher": "StatPearls Publishing",
    "publisher_location": "Treasure Island (FL)",
    "pubmed_id": "39057130\n26421650\n19990373\n34274613\n28135560\n29405964\n2990199\n33685819\n33416290\n22877883\n36286620\n34219021\n20673583\n696779\n34669197\n39048306\n31542087\n20728069\n29229282\n21522146\n33550107\n10985885\n30612545\n28892119\n12504931\n33422446\n29083593",
    "sections": [
        {
            "chapter": null,
            "title": "Continuing Education Activity"
        },
        {
            "chapter": null,
            "title": "Introduction"
        },
        {
            "chapter": null,
            "title": "Etiology"
        },
        {
            "chapter": null,
            "title": "Epidemiology"
        },
        {
            "chapter": null,
            "title": "Pathophysiology"
        },
        {
            "chapter": null,
            "title": "Histopathology"
        },
        {
            "chapter": null,
            "title": "History and Physical"
        },
        {
            "chapter": null,
            "title": "Evaluation"
        },
        {
            "chapter": null,
            "title": "Treatment / Management"
        },
        {
            "chapter": null,
            "title": "Differential Diagnosis"
        },
        {
            "chapter": null,
            "title": "Staging"
        },
        {
            "chapter": null,
            "title": "Prognosis"
        },
        {
            "chapter": null,
            "title": "Complications"
        },
        {
            "chapter": null,
            "title": "Consultations"
        },
        {
            "chapter": null,
            "title": "Deterrence and Patient Education"
        },
        {
            "chapter": null,
            "title": "Enhancing Healthcare Team Outcomes"
        },
        {
            "chapter": null,
            "title": "Review Questions"
        },
        {
            "chapter": null,
            "title": "References"
        }
    ],
    "title": "StatPearls"
}