Suppression of Lactation-HTLim 1t al.,s, BRrInSH 84 1 1 coer16 uppression of actation-H~akim et al. MEDICAL JOURNAL a thrombus (Wessler and Reimer, 1960). Daniel et al. (1968) suggested that very high levels of plasma factor IX may be related to the development of puerperal venous thrombosis. It would appear reasonable to avoid the use of therapeutic agents which give rise to excessive or prolonged increases in factor IX levels during the puerperiuim. If lactation is to be suppressed with oestrogen it is preferable to use the smallest dose that proves effective.The present study has shown that intramuscular hexoestrol has a theoretical advantage over oral stilboestrol in that the increase in factor IX levels is not so great and is of a shorter duration. With most hexoestrol-treated patients plasma factor IX has reverted to normal by the time they leave hospital.We are grateful to Dr. W. R. Pitney for instruction in the technique of factor IX estimations and for his advice at all stages, and to Ortho Pharmaceutical Limited for a supply of factor-IXdeficient plasma and for financial assistance with the study. British Medical Journal, 1969, 4, 84-86 Summary: In a study of early abortions (less than 16-week pregnancies) no significant increase in fetomaternal haemorrhage was found in patients having either threatened or incomplete abortions. A statistically significant increase in fetal cells in the maternal circulation, however, occurred after curettage. The administration of oxytecic drugs in conjunction with curettage in cases of incomplete abortion did not increase the incidence of transplacental passage of fetal erythrocytes when compared with curettage alone. Of the 81 patients curetted following abortion four had a feto-maternal haemorrhage of more than 0-2 ml. The largest amount of fetal blood found in the maternal circulation was 0 4 to 0 5 ml. Preliminary data evaluating the indirect Coombs test and enzyme-treated red cells in Rh-negative post-abortion cases suggest that this amount of blood is not a primary immunizing dose but a " booster " to preformed antibody.