Hydrops fetalis caused by α-thalassemia: An emerging health care problem

Abstract

Recent advances in molecular genetics have provided insights into the mutations and pathophysiology causing α-thalassemias, as well as definitive clinical diagnostic tests for adult carrier detection and prenatal diagnosis. Hydrops fetalis caused by α-thalassemia is found primarily though not exclusively among couples of southeast Asian origin, and is encountered in increasing numbers in North America and elsewhere. These pregnancies inevitably result in fetal death during the third trimester of gestation or shortly after birth, and frequently are associated with serious maternal morbidity and even mortality. Presently, most couples at risk for conceiving fetuses with this serious genetic disorder are not identified. Other at risk couples are recognized only after the birth of one or more hydropic newborns, or hydrops fetalis is detected by ultrasonography during the second trimester of a pregnancy. The correct diagnosis of these hydropic fetuses is sometimes missed at autopsy. After experiencing the horrendous obstetrical, medical, and psychosocial problems associated with such pregnancies, many couples would decide against becoming pregnant again, and some would even request sterilization. A recurring theme of the many case reports of this syndrome is that the correct diagnosis could have been made early in pregnancy, should the physicians have been alert to this diagnostic possibility. They reaffirm the need for public education, both for the medical community and for the population at large. Blood counts are often performed as part of the medical examinations, particularly on all pregnant women during their first visits to physicians. A low MCV result is the screening test for carriers of the thalassemias. With carrier detection, timely genetic counseling, and the availability of prenatal diagnosis during early pregnancy, many couples at risk will be spared of serious medical and psychological ordeals in their quest for having families with children. It is therefore essential that this genetic disorder is recognized, so that the appropriate maternal health care and preventive measures can be provided to the affected couples and communities.