One tablet of 3 mg of warfarin was provided daily to each patient in Warfarin group and placebo to Placebo group. After starting the treatment; weekly follow up of the patient for four weeks till 36 weeks and 2 weeks thereafter. Each follow up visit the following were done; assessment of the amniotic fluid, biophysical profile including non stress test (NST), Doppler U/S of fetal ascending aorta, uterine, middle cerebral and umbilical arteries. Laboratory measurement of prothrombine time and concentration and INR are checked daily until in the therapeutic range for 2 consecutive days, then twice a week for 1-2 weeks, then weekly until stable. Change in a patient's condition, e.g. liver disease, intercurrent illness, and new drug started necessitates more frequent testing. Patients should be advised to report any bruising or bleeding immediately, as advised, avoid aspirin but use paracetamol for pain ,avoid contact sports and activities carrying a risk of head injury. During labor or cesarean section visual inspection of blood loss and 48 hours follow up for the occurrence of hematomas and neonatal follow up for any bleeding problems. Discontinuation of treatment was done if after two weeks of treatment no changes of the amniotic fluid, manifestation of fetal distress appeared or the patient completed 36 weeks of gestation.