Fetal Distress and Neonatal Death After Thoracoamniotic Shunting Therapy Due to Hydrops Associated With Transient Abnormal Myelopoiesis.

We present the case of a pregnant woman who developed fetal bradycardia, which required an emergency cesarean delivery immediately after thoracoamniotic shunting (TAS), resulting in neonatal death four hours after birth due to hemodynamic deterioration. A 35-year-old Japanese female was referred to our hospital at 30 weeks of gestation due to fetal hydrops. Blood and ultrasonography examinations suggested that transient abnormal myelopoiesis (TAM) due to trisomy 21 could contribute to the development of hydrops fetalis. We performed thoracocentesis and TAS replacement as well as chromosomal testing of the amniotic fluid. However, the fetus developed persistent bradycardia soon after the treatment, and a sonographic examination revealed a recurrence of fluid retention in the thoracic cavity. A 1,558-g male neonate received life-saving resuscitation after being born via emergency surgery. Blood analysis revealed the occurrence of TAM in utero. At autopsy, there were no injuries to the intrathoracic organs. The G-banded karyotype revealed trisomy 21 (47, XY, +21). Our case offers new perspectives on providing prenatal information about potential complications to family members and selecting fetuses for TAS in the case of trisomy 21 complicated with TAM.