Methods of assessment of the arterial pulse wave in normal human pregnancy

The study was undertaken to obtain normal values for characteristics of the peripheral arterial pulse wave, in nonpregnant women and in pregnant women at three different stages of gestation, with two devices, to describe cardiovascular hemodynamic variables induced by pregnancy.

Sixty pregnant women were enrolled in the study at three stages of pregnancy, 17 to 20 weeks, 25 to 28 weeks, and 33 to 36 weeks gestation. Results are presented for 53 of these subjects who remained normotensive throughout pregnancy. The values measured were compared with those from 10 nonpregnant women. The two devices used were the SphygmoCor and a monitor invented and developed by Professor Edward Hon, not yet commercially available, referred to in this article as the "Hon" monitor.

An increase in heart rate was observed in all pregnant women. Blood pressure values were lower in pregnancy than in normal nonpregnant women. With respect to the SphygmoCor, the time from the start of the arterial waveform to the second peak/shoulder, was significantly shorter, and augmentation pressure and augmentation index were significantly lower in pregnancy. Data obtained from the "Hon" monitor showed no significant differences in pulse wave arrival time, but rapid ejection time was significantly shortened in pregnancy.

The clinical findings confirm the known cardiovascular changes of pregnancy associated with vasodilatation of peripheral vessels and expansion of blood volume. The fall in augmentation pressure and index are consistent with these changes. Rapid ejection time and the time from the start of the arterial waveform to the second peak/shoulder, which should reflect similar cardiovascular physiologic events, were weakly correlated.