Longitudinal study of vascular structure and function during normal pregnancy

• Published in: Ultrasound in obstetrics & gynecology Vol. 49; no. 1; pp. 46 - 53
• Main Authors: Iacobaeus, C., Andolf, E., Thorsell, M., Bremme, K., Jörneskog, G., Östlund, E., Kahan, T.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.01.2017; Wiley Subscription Services, Inc
• Subjects: Acetylcholine; Adaptive systems; Adult; Augmentation; Blood flow; Blood pressure; Blood volume; cardiovascular risk; Carotid artery; Carotid Artery, Common - diagnostic imaging; Correlation analysis; Doppler effect; endothelial function; Endothelium; Female; Femur; Fetuses; Forearm; Forearm - blood supply; Gestation; human; Humans; Hyperemia; Longitudinal Studies; Medicin och hälsovetenskap; Microcirculation; Microvasculature; Perfusion; Postpartum; Pregnancy; Prospective Studies; Skin; Sodium; Sodium nitroprusside; Structure-function relationships; Ultrasonography, Prenatal; Ultrasound; vascular function; Vasodilation; Veins & arteries; Velocity; Wave analysis; Wave velocity; endothelial function; blood pressure; vascular function; pregnancy; cardiovascular risk; human; microcirculation
• ISSN: 0960-7692; 1469-0705; 1469-0705
• DOI: 10.1002/uog.17326

ABSTRACT Objective To examine alterations in maternal vascular structure and function during normal pregnancy. Methods We assessed brachial and central blood pressure, pulse‐wave velocity and augmentation index (by pulse‐wave analysis and applanation tonometry), common carotid artery structure (by ultrasonography) and endothelial function in the brachial artery (by postischemic hyperemia‐induced flow‐mediated vasodilatation by glyceryl trinitrate) and in the forearm skin microcirculation (by laser Doppler perfusion imaging during iontophoretic administration of acetylcholine and sodium nitroprusside) in 52 healthy nulliparous women at 14, 24 and 34 weeks' gestation, and at 9 months postpartum. Results During pregnancy, brachial and central systolic and diastolic blood pressures initially decreased but subsequently increased (all P < 0.05). Flow‐mediated vasodilatation in the brachial artery increased during early pregnancy (P < 0.05), whereas non‐specific vasodilatation by glyceryl trinitrate decreased (P < 0.01), indicating improved endothelial function. Thus, endothelial function index (forearm blood flow/glyceryl trinitrate) increased during pregnancy (0.30 ± 0.18 in the non‐pregnant state at 9 months postpartum and 0.51 ± 0.19, 0.61 ± 0.39 and 0.49 ± 0.30 in the first, second and third trimesters, respectively) (P < 0.001). Endothelium‐dependent skin microvascular reactivity to acetylcholine also increased (P < 0.01). Carotid–femoral pulse‐wave velocity decreased during pregnancy (5.88 ± 0.91 m/s in the non‐pregnant state and 5.55 ± 0.67, 5.12 ± 0.66 and 5.62 ± 0.74 m/s in the first, second and third trimesters, respectively) (P < 0.001). Conclusion During normal pregnancy, the blood volume expansion necessary for sufficient fetal growth is accommodated by early and marked changes in the matvascular system. This seems to be dependent on normal adaptive endothelial and vascular function. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.