Objective : To assess the effects of antiphospholipid antibodies on pregnancy outcome. Also, the effect of umbiical and uterine arteries Doppler ve-locimetry monitoring on fetal outcome was compared with that of biophysical profile (BPP). Study design : A prospective controlled study that comprised thirty four cases with prolonged activated partial thromboplastin time as the study group and twenty two healthy pregnant women as the control group. Serum samples were kept below -20°C for detection of anticardiolipin antibodies, Doppler velocimetry of umbilical and uterine arteries were done at 6-28 weeks (visit 1), at 29-33 weeks (visit 2) and at 34-36 weeks (visit 3). Fetal biophysical profile scoring was done at 28 weeks and onwards. The end points were pregnancy outcome (abortion, preterm delivery, placental abruption, preeclampsia, IUGR, IUFD, gestational age at delivery, onset of labor, mode of delivery) and fetal outcome (birth weight, perinatal death, Apgar score and neonatal ICU admission). Results : Abnormal uterine and umbilical arteries Doppler FVWs were more frequent in study cases compared with the controls (P