Dilatative fetal cardiomyopathy followed by a mirror syndrome.

Mirror syndrome (Ballantyne syndrome) is a rare condition characterized by maternal edema, which often affects the lungs. It mirrors the image of fetal and placental edema; therefore, it is also called triple edema. We present the case of a 37-year-old secundigravida, referred to our clinic at 26 weeks of a pregnancy complicated by fetal dilatative restrictive cardiomyopathy and hydrops, placentomegaly, new-onset dyspnea, and maternal calf edema. Due to worsening mirror syndrome, preterm labor was induced. Labor was complicated, with soft tissue dystocia, stillbirth, and postpartum hemorrhage. The first pregnancy was also complicated by fetal right ventricular noncompaction dilatative cardiomyopathy. A eutrophic male child was born vaginally at term and died due to deterioration of the cardiac disease in the third year of life. Next-generation sequencing panel for pediatric cardiology was performed in the deceased child and parents. Two gene variants were recorded: MYOM1: c.770_771delCA (p.Thr257fs) and TPM1: c.814G>A (p.Glu272Lys). Both variants were classified as variants of uncertain significance. This case emphasizes the importance of antenatal counseling, the timing of labor induction, appropriate management of possible complications such as postpartum hemorrhage and soft tissue dystocia, and the interpretation of placental biomarkers in the context of mirror syndrome. Finally, it contributes to understanding the clinical significance of the MYOM1 and TPM1 gene variants.