The study population comprised two groups: 5,232 women selected at random from the Makassed hospital outpatient obstetric clinic and 12,169 consecutive deliveries at Makassed hospital.
Among the first group and after approximation to the first percentile, the distribution of blood groups was as follows: A, 44.4%, B, 16.8%, O, 35.2%, AB, 6.6%. 89% were Rh positive and 11% were Rh negative. Among the second group, 3,670 (30%) of the mothers had blood group O Rh positive and 1,530 of them gave birth to A or B infants. Thirty percent of these mothers were immune to the A and/or B antigens. Of 1,320 Rh negative mothers 727 gave birth to Rh positive infants. In total 0.3% of all mothers included in the study gave birth to infants with fetomaternal incompatibility.
Although the extent of passive immunization of Rh negative mothers was not determined, the authors conclude that "the extent of precautions and the methodology of its use are still inappropriate"