NT-proBNP: A Useful Biochemical Marker for Prognosis in Rh-Isoimmunized Pregnancies

Rh incompatibility sometimes results in life-threatening conditions in fetus like severe anemia and jaundice, leading to kernicterus and even death. Even after an uneventful intrauterine transfusion (IUT), fetus may not survive despite correction of the fetal anemia. Finding appropriate markers may help in determining the prognosis of such cases. The N-terminal prohormone of brain natriuretic peptide (NT-proBNP) suggests some degree of heart failure.

Present study was planned to evaluate its role in predicting the outcome of fetus in Rh-isoimmunized pregnant woman.

This prospective study consisted of total 40 pregnant patients: 10 pregnant Rh-isoimmunized women with hydropic fetuses, 10 with non-hydropic fetuses and 20 control group. If the MCA-PSV was > 1.5 MOM, cord blood sampling and IUT was done and sent for fetal hematocrit and NT-proBNP.

The levels of NT-proBNP at various periods of gestation in hydropic, non-hydropic and control group fetuses showed positive correlation with the degree of fetal anemia.

Correlation of high levels of NT-proBNP to fetal anemia proves that hydrops fetalis is probably due to progressive high cardiac output myocardial failure, increased capillary permeability and perhaps reduced coronary flow.