Hydrops fetalis

Detection of hydrops fetalis during an ultrasound examination triggers in our minds several questions. Is this a hydrops or something else? How significant for the pregnancy is this finding? What is the cause? What is the prognosis for this and future pregnancies? What to tell the parents? How to counsel them incorporating all of the previous information to help them make the best possible decision? This article presents the available evidence to help to answer those questions. Hydrops fetalis is usually separated into immune and nonimmune hydrops (NIH) based on the presence or absence of fetal anemia secondary to red cell alloimmunization, respectively. This article is mostly concerned with the latter because the management of immune hydrops fetalis, with few exceptions, follows the guidelines for red cell alloimmunization without hydrops.