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Hydatidiform mole

  • Definition

    A hydatidiform mole is a rare mass or growth that forms inside the uterus at the beginning of a pregnancy. It is a type of gestational trophoblastic disease (GTD).

    See also:

    • Gestational trophoblastic disease
    • Choriocarcinoma (a cancerous form of GTD)

    Alternative Names

    Hydatid mole; Molar pregnancy


    Causes, incidence, and risk factors

    A hydatidiform mole, or molar pregnancy, results from over-production of the tissue that is supposed to develop into the placenta. The placenta normally feeds a fetus during pregnancy. In this condition, the tissues develop into an abnormal growth, called a mass.

    There are two types:

    • Partial molar pregnancy
    • Complete molar pregnancy

    A partial molar pregnancy means there is an abnormal placenta and some fetal development.

    In a complete molar pregnancy, there is an abnormal placenta but no fetus.

    Both forms are due to problems during fertilization. The exact cause of fertilization problems are unknown. However, a diet low in protein, animal fat, and vitamin A may play a role.