Hemostatic factors in cases of early pregnancy bleeding were estimated in 16 patients pregnant for 8-12 weeks and compared with established mean values for normal pregnancies (controls). During abortion there was a significant decrease in platelet count and clot retraction and an increase in capillary fragility, indicating utilization of hemostatic factors. However, the whole blood clotting time was shortened. Subsequent recovery in the postabortive period occurred at a slower rate than that of the recovery previously established for normal delivery (mean platelet count, 268+ or -52 times 10(3)/cu. cm 6-10 days after abortion; 410+ or -103 times 10(3) in corresponding puerperal period). The state of enhanced hemostasis observed 6-10 days after normal labor did not manifest fully after abortion. Abortion resulted in a significant reduction of hemoglobin percentage which was maintained for 10 days. A depressed state of hemopoiesis in abortion might be in part responsible for the persistence of lowered hemoglobin reported in the postabortive period. A case of hemopoietic failure as a result of pregnancy is described, and it is suggested that therapeutic abortion in such conditions may be life-saving.