ABO and Rho(D) blood groups in IMSS population in the State of Nuevo León (estimation of simple and double incompatibility frequency in married couples and their offspring).

ABO and Rho (D) blood groups were studied in 61,023 people receiving medical care at the medical units or blood banks of the Instituto Mexicano del Seguro Social in the metropolitan area in the city of Monterrey, Nuevo León, so as to determine the genetical inheritance patterns that control these blood antigens, and that were used in the stimation of ABO and Rho (D) incompatibility in married couples and in births with maternal fetal incompatibility. It was found that IMSS populations, regardless of the medical units, can be considered as part of the same one and are different to those observed in blood banks. From the married couples, 28.58 percent were found to be incompatible with ABO and 7.15 percent with Rho (D); in 2.04 percent of cases, maternal fetal incompatibility had a ratio of 15.63 percent in the ABO group and 5.60 percent in the Rho (D) group. Double incompatibility was found in 0.88 percent of cases. The importance of these facts is stressed, considered as significant data for neonatologists and for those working in maternal fetal isoimmunization clinics.