Anti-B antibodies in Pregnancy and After Birth

Anti-B

Blood Group: ABO

Common: Yes, especially among blacks. 62.7% of black type O people have anti-B

Causes HDN: Yes

Critical Titer: 1:16

Information:

One of the important things to note is that there is a difference in the severity of HDN based on race. HDN due to anti-A or anti-B is more severe in blacks and latinos than in whites [2, 3]. It is possible to have both anti-A and anti-B at the same time [7]. It is especially important that black infants are not discharged from the hospital prematurely and without proper follow up when ABO incompatibility is suspected. It has been suggested that a 6 hour bilirubin can determine the risk for significant hyperbilirubinemia (4 mg/dL) or severe HDN (6 mg/dL) due to ABO incompatibility [1].

ABO HDN remains the most frequent cause of severe and early jaundice in newborns [4]. Treatments include exchange transfusion and IVIG in addition to phototherapy. Exchange transfusion can lead to a 44.03% reduction in indirect bilirubin [6]. IVIG can reduce the need for exchange transfusion [4, 5]. One study suggests that maternal titers >1:512 can be good predictors of the need for IVIG and exchange transfusion [8], while another study says that titers aren’t useful in predicting the need for exchange transfusion [9].

In general HDN from Anti-B is viewed as being more severe than anti-A. This is because severe HDN due to anti-B is seen more frequently than severe HDN due to anti-A, however anti-A can cause severe HDN too. [10]. Another study said that anti-A and anti-B occur with almost the same frequency and there is no difference in severity [11].

There are multiple reports of severe HDN due to anti-B [12, 13, 14, 15]. While rare, anti-B can affect baby in utero and is capable of causing hydrops [14] and fetal distress requiring emergency c section [12, 13]. Anti-B can also affect baby after birth and cause severe anemia within hours [14, 15].

Articles:

1 - https://www.ncbi.nlm.nih.gov/pubmed/11927726

2 - https://www.ncbi.nlm.nih.gov/pubmed/7117940

3 - https://www.ncbi.nlm.nih.gov/pubmed/856960

4 - https://www.ncbi.nlm.nih.gov/pubmed/25125032

5 - https://www.ncbi.nlm.nih.gov/pubmed/15590442

6 - https://www.ncbi.nlm.nih.gov/pubmed/8284577

7 - https://www.ncbi.nlm.nih.gov/pubmed/18793871

8 - https://www.ncbi.nlm.nih.gov/pubmed/19703120

9 - https://www.ncbi.nlm.nih.gov/pubmed/1082679

10 - https://www.ncbi.nlm.nih.gov/pubmed/11508073

11 - https://www.ncbi.nlm.nih.gov/pubmed/22595217