Anti-PP1Pk (anti-Tja) and habitual abortion.

Blood group incompatibility as a cause of early or habitual abortion has been a matter of much debate. However, the abortion rate in such cases is much higher than that found in the general population. Two sisters having the rare genotype pp and anti-PP1Pk (anti-Tja) in their serum were reported as having habitual abortions; a third sister, with a normal P group, had a normal obstetric history. The relationship of anti-PP1Pk (anti-Tja) to the high rate of habitual abortion was discussed and added support was given to the existing evidence that certain maternal blood group antibodies can affect embryos early in uterine life.