Diagnosis
It is commonly expected to simultaneously identify maternal and fetal findings to diagnose Mirror syndrome. However, described cases in the literature show that this is not always the case and fetal findings may predate maternal presentation and vice-versa. This pattern needs to be kept in mind to allow for diagnostic accuracy and inclusion of Mirror syndrome in differentials.
Maternal presentation in Mirror syndrome is significantly similar to that of PE; both include elevated arterial pressure, edema, weight gain and proteinuria, which makes differentiating between the two one of the biggest diagnostic challenges in patients with this symptomatology. The unique features of Mirror syndrome include younger gestational age at diagnosis (Mirror syndrome has an earlier onset with more than 50% of cases diagnosed between 26.5 and 27.5 weeks4) and maternal presence of hemodilution (decrease in hematocrit and hemoglobin).
Fetal presentation of hydrops fetalis is also a differentiating factor; it is characterized by excessive fluid accumulation within the fetal extravascular components and body cavities. It can have different etiologies and determining the exact cause is important for management of Mirror syndrome.