School of Science and Health, Western Sydney University, Campbelltown Campus, Locked Bag 1797, Penrith, Sydney, NSW, 2751, Australia.
School of Medicine, Western Sydney University, Sydney, Australia.
Clin Auton Res. 2017 Dec;27(6):401-406. doi: 10.1007/s10286-017-0439-1. Epub 2017 Jul 3.
Muscle sympathetic nerve activity and baroreflex sensitivity were examined at rest before, during (weeks 6, 11, 17, 22, 25, 33 and 36) and after a normotensive pregnancy.
Muscle sympathetic nerve activity is elevated during pregnancy with a large peak in the first trimester (Δ17 bursts/min) and a secondary peak in the third trimester (Δ11 bursts/min). Cardiac baroreflex sensitivity peaked in the first trimester (10 vs. 6 ms/mmHg pre-pregnancy), whereas sympathetic baroreflex sensitivity was greater throughout.
The increase in sympathetic outflow early in pregnancy cannot be explained by a reduction in baroreflex sensitivity, while the secondary increase in burst frequency in the third trimester may, in part, be explained by the elevated heart rate.
在正常妊娠前、期间（第 6、11、17、22、25、33 和 36 周）和之后，检查了肌肉交感神经活动和压力反射敏感性。
妊娠期间肌肉交感神经活动升高，在孕早期有一个大高峰（Δ17 次/分钟），在孕晚期有一个次要高峰（Δ11 次/分钟）。心脏压力反射敏感性在孕早期达到高峰（10 比怀孕前 6 毫秒/毫米汞柱），而交感神经压力反射敏感性则一直较高。
妊娠早期交感神经输出的增加不能用压力反射敏感性的降低来解释，而在妊娠晚期爆发频率的第二次增加可能部分解释为心率的升高。
