Chronic maternal cigarette smoking and fetal abdominal aortic blood flow in humans.

Abstract

The abdominal aortic blood flow was measured in 19 fetuses of nonsmoking mothers (NS) and five fetuses of smoking mothers (S) who consumed over 10 cigarettes per day throughout gestation. Serial blood flow measurements beginning in the mid-second trimester to term were made noninvasively with an ultrasonic duplex scanner. Biparietal and transverse abdominal diameters were used to estimate gestational age and fetal weight. Blood velocity spectral waveforms and lumen diameters were used to calculate blood flow (Q, ml/min) and weight normalized blood flow (Q/kg, ml/kg/min). Both Q and Q/kg for the two groups were significantly different by analysis of variance throughout the periods of observation. Third trimester Q and Q/kg (+/- SD) in the S group (738 +/- 20 ml/min and 278 +/- 36 ml/kg/min) were significantly higher (P less than 0.01) than values in the NS group (522 +/- 60 ml/min and 180 +/- 24 ml/kg/min). A redistribution of blood flow to the placenta resulting from an increase in fetal systemic vascular resistance is postulated.