Clinical Data
A systematic review by Allarakia et al.4 included 113 patients with Mirror Syndrome diagnosed between 1956 and 2016. They found that gestational age at presentation varied between 16 to 39 weeks with a mean of 27 weeks. In 46.0% of cases maternal and fetal findings were diagnosed simultaneously, in 41.0% fetal findings preceded any maternal alterations and in the remaining 13.0% maternal findings were first to appear. Most common maternal manifestation was weight gain or edema, present in 84.0% of cases, followed by hypertension in 60.1% and anemia or low hematocrit in 51.3%. The majority of fetuses presented with hydrops fetalis (94.7%) or placental edema (62.8%). Associated conditions were deemed to not influence overall fetal mortality, they were: fetal anemia (16.8%), Rh-isoimmunization (16.8%), multiple gestation pregnancy (16.8%), twin-to-twin transfusion (13.2%), viral infections (15.9%) and one case of metabolic disorder. Data analysis showed that procedural interventions to correct fetal hydrops (maternal blood transfusion, intrauterine transfusion, amniocentesis, laser ablation therapy, peritoneal-amniotic shunt, thoracoamniotic shunt and aortic valve dilation) were significantly associated with fetal survival, regardless the etiology of the disease; the only other intervention to improve survival was induction of labor. The overall survival rate of fetuses was 32.7% and no maternal mortality was reported. Maternal symptoms were found to be resolved in a median of 5.5 days after delivery; in 8 cases there was complete reversal of maternal symptoms before delivery, following supportive treatment or blood transfusion.