Profound impact of uncomplicated pregnancy on diastolic, but not systolic pulse contour of aortic pressure.

OBJECTIVE

To evaluate the impact of uncomplicated pregnancy on the pulse contour of central aortic pressure.

METHODS

A total of 66 women with singleton pregnancy were grouped according to pregnancy duration: first trimester (T1, n = 22), second trimester (T2, n = 20), and third trimester (T3, n = 24). Non-pregnant healthy women, who took combined oral contraception, were included as controls (C, n = 21). The pulse contour of aortic pressure was obtained with radial applanation tonometry, using a commercial device (SphygmoCor). The influence of reflected waves on the contour was evaluated not only in systole, as usual with pulse contour analysis (systolic augmentation), but also in diastole (diastolic augmentation).

RESULTS

Throughout pregnancy, central systolic and diastolic blood pressure remained unchanged and comparable to values in the non-pregnant state. Systolic augmentation amounted to 8.1 +/- 7.5% of pulse pressure in the control group (mean +/- SD), and there was no statistically significant deviation from this value at any stage of pregnancy (T1, 4.6 +/- 11.4%; T2, 5.0 +/- 9.3%; T3, 4.7 +/- 8.1%). In contrast, the amplitude of the diastolic augmentation wave progressively declined with advancing pregnancy (C, 6.5 +/- 2.4%; T1, 5.2 +/- 3.1%; T2, 3.8 +/- 2.6%; P = 0.002 versus C, T3, 2.3 +/- 2.0%; P < 0.0001 versus C and P = 0.0004 versus T1).

CONCLUSION

The systolic shape of the central aortic pressure contour is left unaltered by pregnancy, implying a finely tuned adaptation of the cardiovascular system to the increased demand for blood flow at all stages of the gravid state. In contrast, the amplitude of reflection waves reaching the aortic root in diastole progressively decreases with advancing pregnancy.