What is ABO hemolytic jaundice?

It is widely known that neonatal jaundice is very common in newborns, and parents need not be overly concerned. ABO hemolytic jaundice is one such type. So, what exactly is ABO hemolytic jaundice? Let’s explore this together.

What Is ABO Hemolytic Jaundice?

ABO hemolytic jaundice—also termed alloimmune hemolysis—is caused by blood group incompatibility between mother and fetus. It most commonly occurs when the mother has blood type O and the fetus has blood type A or B; in such cases, the resulting jaundice tends to be more severe. Less frequently, it may occur when the mother has blood type A and the fetus type B or AB, or when the mother has blood type B and the fetus type A or AB; in these instances, jaundice is typically milder. The following scenarios illustrate this:

1. Approximately 40–50% of ABO hemolytic cases occur in firstborn infants. This is because mothers with blood type O may have previously been exposed—through environmental A- or B-type antigens—to A or B antigens prior to their first pregnancy, thereby developing anti-A or anti-B antibodies. Consequently, hemolysis and subsequent jaundice can occur even during the first pregnancy.

2. Among maternal-fetal ABO incompatibilities, about 51% of ABO hemolytic disease cases arise due to differences in the antigenic strength of fetal red blood cells, leading to variable levels of antibody production.

3. A- and B-type blood group substances present in plasma and tissues can bind to maternal antibodies, thereby reducing circulating antibody levels and contributing to hemolytic jaundice.

The above explains what ABO hemolytic jaundice is. If jaundice appears within 24 hours after birth and the bilirubin level exceeds the normal reference range, prompt phototherapy (blue light treatment) should be initiated—the earlier the intervention, the better the outcome. In severe cases, adjunctive therapies such as intravenous albumin or immunoglobulin may also be required. We hope this information proves helpful to you.