Differences in bloodtypes between a cat and unborn kittens may result in danger to newborns. The risk can be assessed by establishing the bloodtypes of the parents. Breeding advice can be used to prevent potentially lethal combinations of bloodtypes. A test is no guarantee for a complete prevention of death of newborns.
When a kitten with the A serotype (DNA: N/N or N/b) is born from a mother with Serotype B (DNA: b/b), the kitten may die because the mother milk may contain antibodies against the A serotype of the kitten.
The purpose of breeding should be, to prevent a female cat with serotype B (DNA: b/b) from having offspring with the A serotype (DNA: N/b). Consequently, it is recommended to breed a female cat with serotype B (DNA: b/b) to a sire with serotype B (DNA: b/b).