The outlook for hydrops fetalis depends on the underlying condition, but even with treatment, the survival rate for the baby is low. Only about 20 percent of babies diagnosed with hydrops fetalis before birth will survive to delivery, and of those babies, only half will survive after delivery.Click to see full answer. Just so, what causes hydrops in a fetus?Hydrops fetalis, or hydrops, is a condition that occurs when large amounts of fluid build up in a baby’s tissues and organs causing extreme swelling. Immune: occurs when the mother’s immune system causes the baby’s red blood cells to breakdown. most dangerous complication of hemolytic disease of the newborn.One may also ask, how early can fetal hydrops be detected? Serial ultrasound (US) examinations should be performed every 1 to 2 weeks for 8 to 12 weeks after exposure. The most obvious US manifestation of fetal anemia is hydrops (see Fig. 167.1). By the time US evidence of hydrops is present, the fetal hematocrit is likely to be less than 20%. Moreover, how common is fetal hydrops? The incidence of non-immune hydrops is hard to calculate because many cases will result in fetal death and/or miscarriage of the baby, and some will get better on their own, especially when hydrops is the result of an infectious process. The range of incidence is reported at 1 in 1,500 to 4,000 deliveries.Is fetal hydrops genetic?Nonimmune hydrops fetalis occurs when a disease or medical condition disrupts the body’s ability to manage fluid. There are three main causes for this type: heart or lung problems, severe anemia (thalassemia), and genetic defects, including Turner syndrome. The exact cause depends on which form a baby has.