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Changes in baroreceptor sensitivity for heart rate during normotensive pregnancy and the puerperium

Journal Article


Abstract


  • Normal pregnancy is associated with marked changes in cardiovascular haemodynamics, which in part may be due to changes in autonomic control mechanisms. Baroreflex sensitivity for heart rate (BRS) was calculated in the supine and standing positions using power spectral analysis of pulse interval (PI) and systolic blood pressure (SBP) in 16 normotensive pregnant women and 10 normotensive non-pregnant controls. The pregnant women were studied on three occasions during their pregnancy (early, mid- and late gestation) and once during the puerperium. Supine total SBP variability increased between early and late pregnancy by 79% [95% confidence intervals (CI) 30%, 145%; P < 0.001], and supine high-frequency PI variability decreased by 75% (CI 51%, 88%; P < 0.001). Supine BRS fell by 50% (P < 0.001), with values returning to early pregnancy levels in the puerperium, which were similar to those recorded in the control group. Standing SBP variability and BRS values were unchanged du ri ng pregnancy and post partum. The low/high frequency ratio of PI variability, taken as a surrogate measure of sympathovagal balance, increased by 137% (CI 42%, 296%; P < 0.01) in the supine but not the standing position from early to late pregnancy. This was due to a decrease in high-frequency variability rather than to an increase in low-frequency variability, suggesting that these changes may have been due to vagal withdrawal rather than increased sympathetic activity. Normotensive pregnancy is associated with a marked decrease in supine BRS, although the exact mechanisms for these changes remain unclear. Further studies are required to define whether changes in BRS and sympathovagal tone in early pregnancy can be used to predict the onset of pregnancy-induced hypertension.

UOW Authors


  •   Humphries, Allison (external author)

Publication Date


  • 2000

Citation


  • Blake, M. J., Martin, A., Manktelow, B. N., Armstrong, C., Halligan, A. W., Panerai, R. B., & Potter, J. F. (2000). Changes in baroreceptor sensitivity for heart rate during normotensive pregnancy and the puerperium. Clinical Science, 98(3), 259-268. doi:10.1042/cs0980259

Scopus Eid


  • 2-s2.0-0034055513

Start Page


  • 259

End Page


  • 268

Volume


  • 98

Issue


  • 3

Place Of Publication


Abstract


  • Normal pregnancy is associated with marked changes in cardiovascular haemodynamics, which in part may be due to changes in autonomic control mechanisms. Baroreflex sensitivity for heart rate (BRS) was calculated in the supine and standing positions using power spectral analysis of pulse interval (PI) and systolic blood pressure (SBP) in 16 normotensive pregnant women and 10 normotensive non-pregnant controls. The pregnant women were studied on three occasions during their pregnancy (early, mid- and late gestation) and once during the puerperium. Supine total SBP variability increased between early and late pregnancy by 79% [95% confidence intervals (CI) 30%, 145%; P < 0.001], and supine high-frequency PI variability decreased by 75% (CI 51%, 88%; P < 0.001). Supine BRS fell by 50% (P < 0.001), with values returning to early pregnancy levels in the puerperium, which were similar to those recorded in the control group. Standing SBP variability and BRS values were unchanged du ri ng pregnancy and post partum. The low/high frequency ratio of PI variability, taken as a surrogate measure of sympathovagal balance, increased by 137% (CI 42%, 296%; P < 0.01) in the supine but not the standing position from early to late pregnancy. This was due to a decrease in high-frequency variability rather than to an increase in low-frequency variability, suggesting that these changes may have been due to vagal withdrawal rather than increased sympathetic activity. Normotensive pregnancy is associated with a marked decrease in supine BRS, although the exact mechanisms for these changes remain unclear. Further studies are required to define whether changes in BRS and sympathovagal tone in early pregnancy can be used to predict the onset of pregnancy-induced hypertension.

UOW Authors


  •   Humphries, Allison (external author)

Publication Date


  • 2000

Citation


  • Blake, M. J., Martin, A., Manktelow, B. N., Armstrong, C., Halligan, A. W., Panerai, R. B., & Potter, J. F. (2000). Changes in baroreceptor sensitivity for heart rate during normotensive pregnancy and the puerperium. Clinical Science, 98(3), 259-268. doi:10.1042/cs0980259

Scopus Eid


  • 2-s2.0-0034055513

Start Page


  • 259

End Page


  • 268

Volume


  • 98

Issue


  • 3

Place Of Publication