Doppler ultrasound measurement of cerebral blood flow in healthy pregnant women

Purpose To compare global cerebral blood supply in healthy pregnant women and nonpregnant women. Materials and Methods Flow volumes in the common, internal, and external carotid, arteries and the vertebral arteries were determined using color Doppler ultrasonography in 17 nonpregnant women, 55 healthy pregnant women at 10 to 40 weeks gestation, and 24 puerperal women within 1 week after spontaneous delivery. Global cerebral blood flow was defined as the sum of flow volumes in the bilateral internal carotid and vertebral arteries. Results In the nonpregnant group, mean flow volumes of the common, internal, and external carotid arteries and the vertebral arteries, and mean global cerebral blood flow volume were (mean±SD) 863±108 ml/min, 554 ±94 ml/min, 386±65 ml/min, 115±24 ml/min, and 669±104 ml/min, respectively. During the second trimester, flow volumes of the common and external carotid arteries increased significantly in the healthy pregnant women, to about 130 percent and 140 percent of the nonpregnant level, respectively. Global cerebral blood flow volume remained unchanged during pregnancy. Conclusion During pregnancy, increase in flow volumes in the common carotid arteries were accompanied by elevated flow volumes of the external carotid arteries but not the internal carotid arteries. This distribution would tend to regulate the volume of global cerebral blood flow throughout the period of pregnancy.