Raised uterine artery impedance is associated with increased maternal arterial stiffness in the late second trimester

Everett TR et al. – Increasing uterine artery Doppler PI reflects impaired placentation and increasing risk of preeclampsia. Authors show a positive association between uterine artery Doppler PI and both global arterial and aortic stiffness. They also show that increased maternal arterial stiffness is associated with a lower birth weight. These findings may represent evidence of an early effect of impaired placentation on the maternal vasculature. Alternatively, given the association between preeclampsia and later cardiovascular disease, ineffective placentation may result from impaired arterial function.

Methods

• A prospective cohort study was performed. 99 women were recruited from the high–risk obstetric ultrasound clinic in the second trimester; median (±IQR) age and gestation were 33 (29–37) years and 23+6 (23+3–24+4) weeks respectively.
• Transabdominal uterine artery Doppler was performed and mean values recorded.
• Women returned at a later date, median gestation (±IQR) 26+5 (25+6–28+0) weeks, for measurement of blood pressure, augmentation index (AIx) and aortic pulse wave velocity (aPWV).

Results

• Uterine artery PI is positively associated with both AIx (r = 0.4, P <0.0001, 95% CI: 0.22–0.55) and aPWV (r = 0.22, P = 0.03, 95% CI: 0.02–0.40).
• Uterine artery PI is positively associated with both AIx (r = 0.4, P <0.0001, 95% CI: 0.22–0.55) and aPWV (r = 0.22, P = 0.03, 95% CI: 0.02–0.40).
• AIx was significantly higher in women with uterine artery PI > 1.45 (P = 0.003, 95% CI: 3.1–14.9) but not aPWV (P = 0.45).
• AIx, but not aPWV, was significantly higher in women who developed preeclampsia (14% vs 9%, 95% CI: 2.0–8.6, P = 0.0018) or IUGR (11% vs 9%, 95% CI: 0.3–4.2, P = 0.027).
• AIx showed a negative correlation with birth weight z–score (r = -0.25, 95% CI: -0.43 to -0.06, P = 0.013).

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