Anomalous ABO inheritance explained by ovum transplantation.

Modern fertilization techniques can lead to unexpected ABO phenotypes in newborn infants and can raise questions as to maternity, paternity, and infant misidentification. Ovum transplantation can result in an infant with an ABO phenotype that is unexpected, given the birth mother's ABO type.|A group AB, Rh-positive female infant was born to a group O, Rh-positive woman as a result of ovum transplantation. The case report is provided.|The birth mother typed group O, Rh-positive both before and after delivery. The infant typed group AB, Rh-positive on cord blood and heelstick specimens.|Ovum transplantation can result in newborns whose ABO phenotypes are unexpected, in relation to the birth mother's ABO type. To ensure patient privacy, such fertilization techniques may not be clearly documented in the delivery room chart. A complete obstetric history helps prevent repeat phlebotomies, expensive and unnecessary typing studies, and concern of the clinical staff with possible sample or infant misidentification.