A study on cardiac autonomic modulation during pregnancy by non-invasive heart rate variability measurement

Abstract

A study on cardiac autonomic modulation during pregnancy by non-invasive heart rate variability measurement Purpose: Remarkable and uncontrollable changes with modifi cation during pregnancy are connected with the autonomic control and consequently with the heart rate variability (HRV). Heart rate variability is a sum of different mechanisms and if pregnancy is a state of change, these modifi cations could be extracted from HRV analysis. Objective: To assess the effect of pregnancy on heart rate variability among pregnant mothers during fi rst trimester of pregnancy and third trimester of pregnancy. Materials and Methods: HRV was measured for 5 minutes of continuous recording of electrocardiogram (ECG) lead II, using windows based HRV analysis system variowin-HR after obtaining permission from the Institutional Review Board of Government Medical College, Bhavnagar and written consent from 30 pregnant subjects and 30 non-pregnant control subjects at autonomic function lab, Dept of Physiology, Bhavnagar. Result: Frequency domain parameters, very low frequency (VLF), low frequency (LF), high frequency (HF) and HF normalized unit (nu) were signifi cantly decreased and LF (nu) and LF/HF signifi cantly increased in pregnant subject in 3 rd trimester as compared to their 1 st trimester of pregnancy. Time Domain parameters like SDNN, RMSSD, SDSD, NN50 count, pNN50, SD1/SD2, triangular HRV index and average R-R interval were signifi cantly decreased during 3 rd trimester of pregnancy. Conclusion: The inhibition of resting parasympathetic activity or vagal blockage and an increment of the sympathetic modulation during the 3 rd third trimester of gestation in pregnancy as compared to their 1 st trimester and healthy non-pregnant subjects. Sympathovagal imbalance and abnormally low HRV may more pronounce during later stage of normal pregnancy. Key words: Autonomic function test, gestation, heart rate variability, pregnancyOriginal Article INTRODUCTIONThe last three decades have witnessed the recognition of a signifi cant relationship between the autonomic nervous system and cardiovascular mortality, including sudden cardiac death.[1] Heart rate variability (HRV) is a non-invasive, easy and economical technique to assess the status of autonomic nervous regulation of cardio vascular system. Heart with a stable and regular heart beat periodically is now considered as the marker for a poor prognostic for longevity.[2] HRV studies enhance understanding of physiological phenomenon of heart activity especially during pregnancy. The changes in the function of every regulatory system during pregnancy are initiated by ovarian and placental hormones in the fi rst trimester, but may also be modifi ed by placental and fetal endocrine factors as gestational age advances. Pregnancy-induced effects on cardiovascular function are increases in heart rate (HR), stroke volume (SV), and cardiac output. [3,4] These changes result from the interactive effects of a primary reduction in peripheral vascular resistance, [5] cardiac autonomic modulati...

Trends in Heart Rate and Heart Rate Variability During Pregnancy and the 3-Month Postpartum Period: Continuous Monitoring in a Free-living Context

“…However, it is notable that in this study, we did not measure HR levels before pregnancy; thus, it is not possible to confirm whether HR levels returned to prepregnancy levels during the 3-month follow-up. Several studies have shown that HR increases during pregnancy [ 7 , 15 , 21 , 24 ] and decreases again during the postpartum period [ 4 ]. In this study, the detected increase during pregnancy followed the results of the meta-analysis, which included >10,000 HR measurements from >8000 women [ 2 ].…”

“…Most studies have investigated changes in HRV in an episodic manner, using 1-time ECG recording of pregnant women at different gestational weeks or during labor [ 16 - 20 ]. In addition, in most longitudinal studies, 10 to 30 minutes of ECG were recorded from pregnant women once per trimester or monthly during pregnancy [ 7 , 21 - 24 ] and postpartum period [ 4 ]. The recordings were performed while the women were resting in a predefined position (usually supine position) in a laboratory setting.…”

Reducing Psychological Stress in Peripartum Women With Heart Rate Variability Biofeedback: A Systematic Review

“…Most of the cardiac changes occur in the first and second trimesters, with cardiac alterations plateauing in the third trimester (Sanghavi & Rutherford, 2014). Despite all of the increases in cardiac status listed above, HRV markedly decreases in pregnancy across gestation (Gandhi et al, 2014; Kher & Desai, 2015; Reyes-Lagos et al, 2015).…”

Physiological Changes in Cardiovascular System during Normal Pregnancy: A Review

“…44 Variations in systolic and diastolic blood pressures and mean arterial pressure are observed in women across continents probably due to a subjective variation in other factors such as nutrition and anthropometric data. 31,[45][46][47]…”