Monitoring lupus anticoagulant-positive pregnancies with umbilical artery flow velocity waveforms.

The presence of the "lupus anticoagulant" in maternal blood is associated with thrombosis in the placental vessels and a high rate of fetal loss. We followed six pregnancies in four mothers positive for lupus anticoagulant autoantibody with Doppler umbilical flow studies. The women were not treated with any drugs, and clinical management was guided by close fetal surveillance including umbilical flow studies. Umbilical artery flow velocity waveforms detect vascular abnormalities in the fetal umbilical placental circulation and were used as an early indicator of developing disease. All pregnancies produced live-born infants. These cases indicate the potential value of such studies in the management of this group at high risk of fetal loss.