“…With the staining method introduced by Kleihauer, Braun, and Betke (1957) it was shown that appreciable transplacental haemorrhage could occur during the third stage of labour (Zipursky, Hull, White, and Israels, 1959 ;Finn et al, 1961). Krieger (1966), in a study on the appearance of antibodies in the maternal serum, produced evidence that transplacental bleeding could also occur during the antepartum phase. Zipursky, Pollock, Chown, and Israels (1963) found that haemorrhage resulted also from operative procedures which damaged the placental site.…”