Hemoglobin Bart hydrops fetalis: A model for studying vascular changes in placental hypoxia

Contrary to expectations, the overall pattern of vascular changes in Hb Bart HF suggested multifactorial hypoxia: pre-placental, on the basis of the marked placentomegaly, compromising blood flow from uterine distention; placental, from hydropic villi causing a generalized diminished intervillous space; and post-placental from the greatly reduced capacity of Hb Bart to extract oxygen from the intervillous space. Standardized vascular morphometry will facilitate comparison between different conditions, for a better understanding of placental hypoxia.