title: Longitudinal study of vascular structure and function during normal pregnancy.
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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Clinical Sciences, Karolinska Institutet, Danderyd Hospital, Division of Obstetrics and Gynaecology, Stockholm, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Iacobaeus
authors.affiliation: Department of Clinical Sciences, Karolinska Institutet, Danderyd Hospital, Division of Obstetrics and Gynaecology, Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Andolf
authors.affiliation: Department of Clinical Sciences, Karolinska Institutet, Danderyd Hospital, Division of Obstetrics and Gynaecology, Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Thorsell
authors.affiliation: Department of Women's and Children's Health, Karolinska Institutet, Division of Obstetrics and Gynaecology, Stockholm, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Bremme
authors.affiliation: Department of Clinical Sciences, Karolinska Institutet, Danderyd Hospital, Division of Cardiovascular Medicine, Stockholm, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Jörneskog
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Södersjukhuset, Obstetrics/Gynaecology, Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Östlund
authors.affiliation: Department of Clinical Sciences, Karolinska Institutet, Danderyd Hospital, Division of Cardiovascular Medicine, Stockholm, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Kahan
mesh_terms: D000328:Adult; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging*; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D008137:Longitudinal Studies; D008833:Microcirculation; D011247:Pregnancy; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal
keywords: blood pressure; cardiovascular risk; endothelial function; human; microcirculation; pregnancy; vascular function