Uterine artery Doppler flow and uteroplacental vascular pathology in normal pregnancies and pregnancies complicated by pre-eclampsia and small for gestational age fetuses

This study was conducted to investigate the association between uterine art ery Doppler flow patterns and uteroplacental vascular pathology in normal a nd complicated pregnancies in view of the recently described concept of het erogeneous causes of hypertensive pregnancy complications. Forty-three wome n whose pregnancies were complicated by pre-eclampsia, the HELLP (Haemolysi s, Elevated Liver enzymes, Low Platelets) syndrome and/or small for gestati onal age (SGA) fetuses and 27 women with normal pregnancies undergoing elec tive caesarean section were included. We obtained uterine artery Doppler wa veforms at a mean of 4 days before delivery. Placental bed biopsies were ob tained at caesarean section and analysed for physiological changes and path ological changes. We found that abnormal uterine artery Doppler flow was strongly associated with pregnancy complications. Absence of physiological changes was seen in 58 per cent of complicated pregnancies and 40 per cent of normal pregnancie s. Pathological changes were seen in 58 per cent of complicated pregnancies and 53 per cent of normal pregnancies; they occurred in spiral arteries wi th and without physiological changes, and there was no significant correlat ion to Doppler results. In conclusion, absence of physiological changes is associated with abnormal uterine artery Doppler flow and pregnancy complica tions. However, there is a gradient in the severity of uteroplacental vascu lar pathology and the correlation with pregnancy complications is not as st rong as previously thought. There is also a significant degree of uteroplac ental vascular pathology in normal pregnancies with normal uterine artery D oppler flow. This variation may be partly due to sampling error, as a typic al biopsy contains only one or two spiral arteries. We hypothesize that add itional factors might be necessary to induce the clinical syndrome of pre-e clampsia. (C) 2001 Harcourt Publishers Ltd.