Lymphangiomas are uncommon, benign (from a histopathology viewpoint) malformations of the lymphatic system with thin-walled vessels; however, these tumors may be dangerous for fetal or neonatal life. They are observed in 1:6000 newborns at birth and in 1:750 spontaneous abortions. We aimed to investigate the role of fetal echocardiography in the prognosis of lymphangioma. Selected data of 19,836 pregnant women studied between 1999 and 2020 were retrospectively analyzed. In total, 32 cases of lymphangioma meeting the following criteria were further analyzed: (1) ultrasound availability from the 1st trimester of pregnancy and (2) nuchal translucency ≤ 2.5 mm. Echocardiographic findings, karyotype, size, and location of the possible lesion were juxtaposed with the clinical follow-up. The statistical analysis was performed using Statistica 13.1 software (StatSoft, Tulsa, OK, USA). Lymphangioma in the analyzed material coexisted with abnormalities in fetal echo in 78% (n = 25) of cases, especially: heart defect in 50% (n = 16) and with normal heart structure with functional changes in 28% (n = 9). Karyotype was available in 50% of the analyzed cases (n = 16). Normal cytogenetic results were observed in 62.5% (n = 10) of cases. In the remaining cases, the following were observed: Turner Syndrome: 25% (n = 4) and Down Syndrome 12.5% (n = 2). The rate of alive newborns was significantly higher among fetuses with isolated lymphangioma in comparison to those with lymphangioma associated with abnormal ECHO examination: 38.46% (n = 5) vs. 15.38% (n = 2; p = 0.037). Abnormal ECHO exam was a poor prognostic sign for fetuses with lymphangioma; therefore, we think it is important to refer these cases for detailed echocardiography in tertiary centers. Moreover, it should be highlighted that in all lymphangioma cases there was an indication to perform the karyotype assessment, as there was a high risk of aneuploidy.