A twenty-weeks male fetus presented with severe hydrops and splenomegaly. An amniocentesis was conducted to ruled out genetic syndromes and to perform an intrauterine transfusion, with negative maternal serologies and normal karyotype. Fetus blood test revealed haemolytic anaemia (haemoglobin 46 g/L) and severe thrombocytopenia (22 10⁹/L). Peripheral blood smear showed countless circulating nucleated red blood cells, polychromasia in erythrocytes and anisopoikilocytosis [A, May-Grunwald-Giemsa (MGG), 20x]. Striking cytoplasmatic inclusions with needle-like morphology were observed inside the erythroblasts and erythrocytes (B, MGG, 100x). These inclusions were suggestive of crystallised porphyrins. The fetus peripheral blood showed porphyrin fluorescence at orange range (615-617 nm) with the mercury lamp (C, fluorescence microscopy, 100x). The amniotic fluid was analysed and porphyrinuria was confirmed given the positive red fluorescence (fluorimetric emission peak of 619 nm) under ultraviolet light (left), compared to a healthy control (right) (D, ultraviolet exposure). The type I coproporphyrins measured by reverse-phase high-pressure liquid chromatography (HPLC) with fluorescence detection were elevated at the amniotic fluid [8300 nmol/L (normal range: <20 nmol/L)]. Congenital erythropoietic porphyria (CEP) or Günther porphyria, caused by uroporphyrinogen III synthase deficiency, was then diagnosed. The parents finally decided to stop the pregnancy, and a homozygous variant in NM_000375.3(UROS):c217T>C(p.Cys73Arg) was detected in the fetus by Sanger method, which is correlated with severe phenotype of CEP.