Hydrometra is characterized by an enlarged uterus due to the accumulation of hypoechogenic fluid (Lêga and Toniollo, 1999), presence of mobile, echogenic and relatively thin trabeculae, and the absence of placental structures or other signs of the preHydrometra is characterized by an enlarged uterus due to the accumulation of hypoechogenic fluid (Lêga and Toniollo, 1999), presence of mobile, echogenic and relatively thin trabeculae, and the absence of placental structures or other signs of the presence of an embryonic or fetal structuresence of an embryonic or fetal structure