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Sympathetic Neurovascular Regulation During Pregnancy: A Longitudinal Case Study
Author(s) -
Steinback Craig,
Usselman Charlotte,
Davenport Margie
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.1041.8
Subject(s) - medicine , pregnancy , gestation , neurovascular bundle , endocrinology , blood pressure , cardiology , anesthesia , anatomy , biology , genetics
Pregnancy is associated a ~50% increase in blood volume, ~40% increase in cardiac output (Q), offset by a drop in total peripheral resistance (TPR). While limited data indicate a concurrent increase in sympathetic nerve activity (SNA) in normal pregnancy, suggesting reduced transduction of SNA into TPR, longitudinal neurovascular adaptation during gestation remains poorly understood. We conducted a longitudinal assessment of SNA and TPR in a 36 year old woman during her second pregnancy. Measures were made on 2 occasions in the month prior to conception, 4 occasions during pregnancy (9, 24, 30, and 38 wks gestation) and again 10 wks postpartum. Mean arterial pressure (MAP; Finometer) and Q (ModelFlow) were measured and used to calculate TPR. SNA was measured using microneurography (peroneal nerve). There was a gestationally dependent increase in SNA burst frequency (r 2 =0.970, P<0.01) and incidence (r 2 =0.977, P<0.01); frequency (24 bpm to 59 bpm) and incidence (34 b/100hb to 65 b/100hb) increased 145% and 89% respectively by 38 wks compared to early follicular values. However, transduction (TPR/SNA Burst Frequency) decreased throughout pregnancy (r 2 =0.952, P<0.05; 0.80 au to 0.21 au). By 10 wks postpartum, SNA (24 bpm; 28 b/100hb) had returned to pre‐pregnant values whereas transduction (0.44au) remained lower. These longitudinal data highlight the progressive sympoathoexcitation during pregnancy which is offset by a concurrent reduction in neurovascular transduction. Sympathetic hyperactivity reverses early in the post‐partum whereas transduction remains decreased. Funded by WCHRI, NSERC, HPF