We observed that the distribution of blood groups of AB0 system is in accordance with previous findings of our authors. Besides, data on the distribution of Rh negative groups in the adult populations studied in 1976,1977 and 1982 are in agreement with data from literature. However, the distribution of Rh negative groups is significantly decreased both in prematurely born twins (12.18%) and in maturely born babies (12.41%). We maintain that further studies are needed to confirm these results.
