Changes in vascular function and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight

• Published in: Journal of obstetrics and gynaecology Vol. 42; no. 4; pp. 607 - 613
• Main Authors: Benvenuto, Silvia, Joo Turoni, Claudio, Marañón, Rodrigo O., Chahla, Rossana, Peral de Bruno, María
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 19-05-2022; Taylor & Francis Ltd
• Subjects: Arterial stiffness; Autonomic Nervous System - physiology; Female; Heart Rate - physiology; heart rate variability; Humans; Nervous system; Parasympathetic Nervous System - physiology; parasympathetic system; Pregnancy; Pregnancy Trimester, First; Prospective Studies; sympathetic system; the new-borns weight; parasympathetic system; sympathetic system; Arterial stiffness; heart rate variability; the new-borns weight
• ISSN: 0144-3615; 1364-6893
• DOI: 10.1080/01443615.2021.1945003

This study aimed to evaluate vascular function changes and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight. This prospective study performed in pregnant (PG) women and after delivery (not pregnant: NPG) evaluated the endothelial function (EF) and arterial stiffness (AS) by a non-invasive method. We evaluated the heart rate variability (HRV), parasympathetic nervous system (PNS), sympathetic nervous system (SNS) indexes by electrocardiogram (5 min) and the urinary nitrite excretion (NOx). PG increased EF and NOx and decreased AS and HRV. PG decreased the PNS index and augmented the SNS index. The new-born weight positively correlated with the PNS index (Pearson's r: 0.4291; p<.05), NOx, HRV and negatively correlated with AS. In summary, in pregnancy, although haemodynamically, the SNS activation plays a compensatory role, the low rates of PNS inhibition are essential to ensure normal foetal growth.
Impact Statement
What is already known on this subject? In pregnancy, there are adaptive physiological changes in the cardiovascular system that include increases of EF and decreases AS with an SNS activation. The study of HRV lets to predict the SNS and PNS balance and how they affect blood pressure and vascular function.
What the results of this study add? Although it is known that SNS activation plays a compensatory role in healthy pregnancy, this study adds the critical role of PNS. Early in pregnancy, the low rates of PNS inhibition are essential to ensure normal foetal growth.
What the implications are of these findings for clinical practice and/or further research? The present results show a potential predictive value of SNS and PNS activity early in pregnancy. It will provide valuable information not only on the pregnant woman's vascular function but also on the new-born weight.