A curious case of maternal mirror syndrome secondary to fetal urinary ascites

BackgroundMaternal mirror syndrome is a rare pregnancy complication causing maternal edema that mirrors that of a hydropic fetus. Isolated fetal ascites is also uncommon and has multiple possible etiologies, and has not traditionally been associated with maternal mirror syndrome.Case reportWe present a case of "atypical maternal mirror syndrome" in a fetus with isolated abdominal ascites to illustrate the possibility of mirror syndrome without fetal hydrops. A 32-year-old G1P0 had an ultrasound revealing significant fetal abdominal ascites with incompletely visualized fetal bladder dome. The patient developed pulmonary edema with oxygen requirements and underwent preterm delivery due to concern for mirror syndrome. The neonatal ascites was suspected to be secondary to bladder outlet obstruction due to hydrometrocolpos from an imperforate hymen. Although the fetus was not hydropic, our patient developed pulmonary edema, hemodilution, and maternal weight gain, and recovered quickly after delivery, many features of maternal mirror syndrome.ConclusionThis case illustrates an atypical presentation of maternal mirror syndrome in the setting of isolated fetal ascites rather than fetal hydrops. With the significant maternal and fetal morbidity associated with maternal mirror syndrome, clinicians should consider maternal mirror syndrome as a possible diagnosis even in the absence of fetal hydrops.