Muscle sympathetic nerve activity peaks in the first trimester in healthy pregnancy: a longitudinal case study

Sarah L. Hissen, Khadigeh El Sayed, Vaughan G. Macefield, Rachael Brown, Chloe E. Taylor

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16 Citations (Scopus)

Abstract

Objective and methods: 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. Results: 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. Interpretation: 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.

Original languageEnglish
Pages (from-to)401-406
Number of pages6
JournalClinical Autonomic Research
Volume27
Issue number6
DOIs
Publication statusPublished - 1 Dec 2017

Keywords

  • Baroreflex sensitivity
  • Blood pressure
  • Microneurography
  • Pregnancy

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