Maternal cerebral blood flow during normal pregnancy: a cross-sectional study.

Nevo, Ori; Soustiel, Jean F; Thaler, Israel · Am J Obstet Gynecol · 2010

cross_sectional · Level IV

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Abstract

Pregnancy is associated with substantial changes in the maternal circulatory physiology. Our aim was to investigate maternal cerebral blood flow (CBF) during normal pregnancies. We prospectively measured maternal CBF in 210 low-risk pregnant women at different gestational ages, and in 15 nonpregnant women. CBF was assessed by measuring blood flow volume in the internal carotid artery (ICA) by dual-beam angle-independent digital Doppler ultrasound. ICA blood flow volume increased during pregnancy from 318 mL/min ± 40.6 mL/min in the first trimester to 382.1 mL/min ± 50.0 mL/min during the third trimester, corresponding to CBF values of 44.4 and 51.8 mL/min(-1)/100 g(-1), respectively (P < .0001). CBF changes were associated with progressive decrease in cerebral vascular resistance and moderate increase in ICA diameter. Maternal CBF is gradually increasing during normal pregnancy. Vasorelaxing impact of estrogens and other factors on cerebral vessels may explain the changes in CBF during pregnancy.

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