Hofman, Y.M.C. (2014) Het effect van de vroege zwangerschap op de sympathische activiteit in het maternale cardiovasculaire systeem. thesis, Medicine.
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Abstract
Objective: Hemodynamic adaptation in normal pregnancy leads to a fall in peripheral vascular resistance, triggering a response consisting, among others, of a rise in heartrate (HR) and cardiac output (CO). This response is in part achieved by a higher sympathetic activity. This study aims to explore the role of the sympathetic nervous system in response to early pregnancy by estimating the sympathetic activity by measuring two non- invasive parameters: the pre-ejection period (PEP) and skin conductance (SCL). Research design and methods: This was a prospective longitudinal observational study in 9 healthy, normotensive pregnant women without a history of relevant diseases. We measured PEP and SCL on 3 consecutive occasions in the first trimester of pregnancy. During each session, we assessed PEP and SCL during 1) baseline (30 minutes in supine position) and 2) orthostatic stress, achieved by a mild orthostatic stress-test. The measurement for this study took place by using the VU-AMS, which monitors the electrocardiogram (ECG), the impedance cardiogram (ICG) and SCL. Analysis of raw data took place by using the VU-AMS software. Statistical analysis was performed using SPSS software, using mixed model analysis and correlation tests. Results: Visual inspection of PEP and SCL during baseline, as well as statistical analysis, showed a constant level of PEP and SCL during the first trimester of pregnancy (p PEP = 0,57 and p SCL = 0,77). PEP increases during orthostatic stress ( p <0,05), but the size of increase remained the same in the three consecutive measurements. SCL changes inconsistent during baseline measurements, as well as during orthostatic stress. The PEP and SCL showed a negative correlation (r = -0,412, p = 0,045), which disappears during orthostatic stress. Conclusions: Hemodynamic adaptation in early pregnancy seems not to be attended by a (measurable) increase in sympathetic activity. However, the size of the study group was small, while there was no information available of the amplitude of PEP and SCL before pregnancy. The PEP is not suitable to show reliable changes in cardiac sympathetic activity during orthostatic stress, due to cardiac preload- and afterload effects induced by postural changes. While pregnancy makes progress changes in SCL are inconsistent, as well as the effect of orthostase on SCL. PEP and SCL are correlated during baseline measurements, but it is unclear whether SCL can be used to increase the sensitivity of the PEP, for demonstrating more cardiovascular sympathetic activity. This requires a larger test sample using a different kind of stress-test and analysing by means of multivariate regression. In the follow-up of this study it seems wise to seek for a studygroup as homogeneous as possible, to minimize the influences of other factors on sympathetic activity, such as age, parity, stress, time of measurement etc.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | Linden, Dr. P.J.Q. van der |
| Supervisor name: | Peeters, Dr. L.L.H. and Gynaecologie en obstetrie and Universitair Medisch Centrum Utrecht |
| Faculty: | Medical Sciences |
| Date Deposited: | 25 Jun 2020 10:57 |
| Last Modified: | 25 Jun 2020 10:57 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/1764 |
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