Hydrops fetalis (HF) is a serious fetal condition defined as an abnormal fluid accumulation in fetal extravascular compartments and body cavities caused by either immune or non immune conditions. Immune hydrops is caused by fetal hemolysis medi¬ated by circulating maternal antibodies to fetal red blood cell antigens. Its most common determinant is rhesus incompatibility. Systemic Lupus Eritematosus (SLE) is another rare cause of immune fetal hydrops, when the pregnancy is complicated by the presence of a third degree congenital heart block (CHB). The Neonatal Lupus Syndrome occurs with a prevalence of 2%.
We reported the case of severe fetal hydrops in a 31 weeks pregnant woman affected by mild maternal D alloimmunization and SLE. Despite fetal hydrops and a mild positive indirect Coombs’ test, the flow-rate study with the Systolic Peak Velocity (PSV) of the MCA excluded a fetal anemia. At birth, blood gas showed a condition of severe metabolic and respiratory acidosis (pH 6.43, pO2 9.9 mmHg, pCO2 206 mmHg, Base Excess (BE) -35 mmol/l, HCO3- 2.7 mmol/l) and a mild anemia (Hemoglobin 10.3 g/dl). ECG revealed a normal sinus rhythm and a CHB was excluded. Despite the critical clinical condition, no cardiorespiratory or neurological adverse outcomes occurred in the newbor
