Cardiac output and peripheral vascular resistance during normotensive and hypertensive pregnancy – a systematic review and meta‐analysis

Abstract

Background In‐depth insight into haemodynamic changes during normotensive pregnancy may help identify women at risk for gestational hypertensive complications. Objectives To determine the magnitude of changes in cardiac output and its determinants stroke volume and heart rate, and total peripheral vascular resistance during singleton normotensive and hypertensive pregnancies. Search strategy PubMed (NCBI) and Embase (Ovid) databases were searched from their inception up to November 2019. Selection criteria Studies reporting original measurements of haemodynamic parameters during pregnancy together with a non‐pregnant reference measurement. Studies including women using antihypertensive medication were excluded. Data collection and analysis Pooled mean differences between pregnant and non‐pregnant women, and absolute values of haemodynamic parameters were calculated for predefined gestational intervals using a random‐effects model in normotensive and hypertensive pregnancy. Meta‐regression analysis was used to analyse group differences in adjustments and absolute values during pregnancy. Main results In normotensive pregnancies, cardiac output increased from the first weeks on, reaching its highest level early in the third trimester (mean difference, 1.41 l·min1; 95% CI 1.18–1.63 l·min). In parallel, vascular resistance decreased progressively until its nadir in the early third trimester (mean difference, −331 dyn·sec–1·cm–5; 95% CI −384 to −277 dyn·sec–1·cm–5) and then increased slightly at term. In hypertensive pregnancies, the initial cardiac output increase was higher and vascular resistance did not change throughout gestation compared with reference values. Conclusions Hemodynamic changes in women who eventually develop hypertensive complications are substantially different. Serial monitoring and plotting against developed normograms can identify women at risk and may allow timely intervention. Tweetable abstract Monitoring haemodynamic changes in pregnancy helps identify women at risk for hypertensive complications.

Maternal hemodynamics and neonatal birth weight in pregnancies complicated by gestational diabetes: new insights from novel causal inference analysis modeling

“…We included in the analysis hemodynamic assessments performed between 34 + 0 and 42 + 0 weeks' gestation, since cardiovascular adaptations to pregnancy have already reached their peak and change only minimally during this period 1,2 . If a participant had more than one assessment during this gestational window, the later assessment was included in the analysis.…”

“…After removal of variables showing a high degree of collinearity (demonstrated in Figure S3), the variables retained in the model were CO, MAP, TPR, aortic AIx, PWV and BMI at booking. Our initial DAG did not include an edge between gestational age and CO, PWV or aortic AIx, since the change in these variables during late gestation is less than that at earlier stages of pregnancy 1 . Incorporating an adjustment of these variables for gestational age did not change the results significantly, supporting our initial decision not to include this association.…”

“…It is a strength of this analysis that significant results can be interpreted not just as associations between the variables, but also as causal relationships, in which the change in the hemodynamic variable produces the change in birth weight. A potential limitation is that the gestational age at hemodynamic assessment was earlier in the GDM group compared with the control group, but, since the change in maternal hemodynamics in the late third trimester is relatively small 1,2 , this is unlikely to have impacted the final results. Our study was limited by the inclusion of only English-speaking women, which had an impact on the number of subjects included in the study and thus the sample size, and by the similarity in hemodynamics and birth weight between the control and study groups.…”

“…Normal pregnancy is characterized by an increase in maternal cardiac output (CO) 1,2 and a decrease in mean arterial pressure (MAP) 2 , total peripheral resistance (TPR) 1,2 and central arterial stiffness 3,4 . These changes to the maternal cardiovascular system sustain the increasing uteroplacental perfusion and are closely related to fetal growth.…”

Noninvasive Cardiac Imaging in Formerly Preeclamptic Women for Early Detection of Subclinical Myocardial Abnormalities: A 2022 Update

“…On the one hand, prior preeclampsia is associated with structural and functional vascular changes, as well as cardiac remodeling of the left ventricle that may predispose to microcirculatory shortfall [5]. This remodeling is thought to be a result of cardiac adaptation to an increase in total peripheral vascular resistance during pregnancy from the 29th week onward, which occurs alongside an increase in blood pressure [6][7][8]. On the other hand, macrovascular coronary atherosclerosis is also considered to play a role since formerly preeclamptic women develop coronary artery calcifications on average 5 years earlier than women who underwent a normotensive pregnancy [9].…”