Comprehensive Diagnosis of Fetal Hypoxia in Trisomy 21 Complicated by Transient Abnormal Myelopoiesis and Esophageal Atresia

<p> Transient abnormal myelopoiesis（TAM）in children with trisomy 21 develops mainly in the neonatal period and often resolves spontaneously. Additionally, fetal-onset TAM is rare but has a poor prognosis with reports of fetal and neonatal deaths. In this report, we describe a case of trisomy 21 with TAM diagnosed after birth; although we had difficulty determining placental insufficiency due to fluctuations in amniotic fluid volume due to polyhydramnios associated with esophageal atresia, we diagnosed fetal insufficiency by abnormal fetal blood flow waveforms and changes in fetal heart rate monitoring.</p><p> The patient, a 41-year-old twice-parous woman, was admitted to our hospital because of polyhydramnios due to esophageal atresia. Transabdominal ultrasound examination on admission revealed polyhydramnios with an amniotic fluid index of 38 cm and abnormalities in the umbilical and middle cerebral arterial blood flow waveforms. Amnioreduction was performed due to symptoms of polyhydramnios, after which there was no significant increase in amniotic fluid volume. Thereafter, late decelerations with decreased baseline variability were noted on fetal heart rate monitoring. We diagnosed fetal dysfunction and the pregnancy was terminated. The infant was diagnosed with TAM and trisomy 21, and chemotherapy was started from 2 days after birth with a good prognosis.</p><p> Fetal-onset TAM may be complicated by polyhydramnios due to gastrointestinal atresia associated with trisomy 21, and it may interfere with establishing the diagnosis of fetal hypoxia. Furthermore, combining amniotic fluid volume monitoring with fetal heart rate monitoring and fetal blood flow Doppler studies may be effective in diagnosing fetal hypoxia, even in infants with TAM.</p>