Ultrasonographic severity scoring of non-immune hydrops: A predictor of perinatal mortality

Aim: To develop an ultrasonographic severity scoring of non-immune hydrops in order to predict perinatal outcomes in women with non-immune hydrops. Methods: The study population consisted of pregnant women who were admitted and delivered with the diagnosis of fetal non-immune hydrops and singleton gestation. Cases were divided into "perinatal survivor" and "perinatal non-survivor" groups. Perinatal non-survivor cases were defined as those with stillbirth or neonatal death ≤28 completed days after birth. The presence of an abnormal fluid collection in each body compartment, such as subcutaneous edema, pleural effusion, pericardial effusion, or ascites was assigned a score of 1 point per each body compartment, and the absence of abnormal fluid collection was scored as 0 point. The total number of abnormal fluid collections was converted to a numeric score, which was called the ultrasonographic severity scoring of nonimmune hydrops (USNIH). Results: Perinatal death occurred in 46.5% (20/43) of the cases of non-immune hydrops. USNIH in patients of the non-survivor group was significantly higher than that in those of the survivor group [non-survivor group 3 (2-4) vs. survivor 2 (2-3); median (range); P<0.05]. Perinatal mortality rates were higher in patients with USNIH ≥3 points than in those with USNIH of 2 points (67% vs. 13%, P<0.005). This difference remained significant after adjustment for confounding variables. When confining analysis to those with idiopathic non-immune hydrops, women in the perinatal non-survivor group had significantly higher USNIH score than those in the perinatal survivor group, and this difference remained significant after adjustment. Conclusions: Our USNIH system may be a reliable predictive marker for perinatal outcomes in cases of non-immune hydrops, especially in idiopathic hydrops during the antenatal period.