Bioimpedance cardiography in pregnancy: A longitudinal cohort study on hemodynamic pattern and outcome

Abstract

BackgroundPregnancy associated cardiovascular pathologies have a significant impact on outcome for mother and child. Bioimpedance cardiography may provide additional outcome-relevant information early in pregnancy and may also be used as a predictive instrument for pregnancy-associated diseases.MethodsWe performed a prospective longitudinal cohort trial in an outpatient setting and included 242 pregnant women. Cardiac output and concomitant hemodynamic data were recorded from 11th–13th week of gestation every 5th week as well as at two occasions post partum employing bioimpedance cardiography.ResultsCardiac output increased during pregnancy and peaked early in the third trimester. A higher heart rate and a decreased systemic vascular resistance were accountable for the observed changes. Women who had a pregnancy-associated disease during a previous pregnancy or developed hypertension or preeclampsia had a significantly increased cardiac output early in pregnancy. Furthermore, an effect of cardiac output on birthweight was found in healthy pregnancies and could be confirmed with multiple linear regression analysis.ConclusionsCardiovascular adaptation during pregnancy is characterized by distinct pattern described herein. These may be altered in women at risk for preeclampsia or reduced birthweigth. The assessment of cardiac parameters by bioimpedance cardiography could be performed at low costs without additional risks.

Methods and considerations concerning cardiac output measurement in pregnant women: recommendations of the International Working Group on Maternal Hemodynamics

“…As early as the first trimester of pregnancy, a rapid increase in CO occurs that continues throughout the second trimester 1,22,23 . There is a debate in the literature concerning the changes in CO during the third trimester; some studies found a decline 7,[24][25][26] , whereas others observed no change 2,5,6,27 or an increase towards term 28,29 .…”

Autonomic imbalance captures maternal and fetal circulatory response to pre-eclampsia

“…The hypovolemia is associated with an increased sympathetic activity [ 4 , 5 ]. The elevated autonomic balance is an evident marker of augmented peripheral vascular tone and hypoperfusion of the end-organs [ 3 ].…”

“…The insufficient invasion causes the well-known placental synthesis of pro-inflammatory substances and vasoconstrictors. Placental ischemic syndrome is an initial event in the scenario of PE [ 3 , 4 , 6 ]. Further endothelial dysfunction, oxidative stress and thrombophilia enhance vasoconstriction.…”

“…Further endothelial dysfunction, oxidative stress and thrombophilia enhance vasoconstriction. The prediction of PE requires the investigation of different biochemical and biophysical markers [ 1 – 3 ].…”

“…HRV captures the impact of central and peripheral circuits of regulation on hemodynamics [ 5 ]. The sympathetic overactivity could be speculated as a preclinical sign of PE [ 3 , 5 ].…”