Report on a 24 years old first pregnant woman with chronic pyelonephritis, treated for 1 1/2 years, also during pregnancy, with high doses of rifampicin (1200 mgs/day). After normal delivery in the 42 th. week of pregnancy there were bleedings both in mother and newborn with demonstrable temporary disturbances in liver-function and coagulation system. Especially the coagulation factors produced in the liver were concerned. The complications after rifampicin carried out the conclusion that rifampicin should be given in pregnancy only with exact indication.