Valsalva manoeuvre can be used to study baroreflex sensitivity in pregnancy

Objective: The aim of this study was to assess whether baroreflex sensitivity call be measured in a non-invasive manner with the Valsalva manoeuvre in pregnancy. Study design: Baroreflex sensitivity was measured from the reflex response to phenylephrine injection and phase four of the Valsalva manoeuvre in nine pregnant women at 27 (range 24-33) gestational weeks. Results: Both the phenylephrine test and the Valsalva manoeuvre yielded similar estimates of baroreflex sensitivity (9.3 (4.1) ms/mmHg vs. 8.0 (5.2) ms/mmHg, Pearson's correlation coefficient r=0.81, P<0.008, linear regression BRSValsalva (ms/mmHg) = 1.03xBRS(Phenylephrine) + 1.59). Comparable changes in heart rate and blood pressure were obtained with the phenylephrine test and the Valsalva manoeuvre. Conclusion: The physiological challenge caused by the Valsalva manoeuvre can be used to measure baroreflex sensitivity in pregnancy. A possibility to study baroreflex function non-invasively, without pharmacological intervention, benefits future research of blood pressure regulation in pregnancy. (C) 1998 Elsevier Science Ireland Ltd.