title: Change in maternal cardiac output from preconception to mid-pregnancy is associated with birth weight in healthy pregnancies.
abstract: OBJECTIVE
  Birth weight (BW) is thought to be determined by maternal health and genetic, nutritional and placental factors, the latter being influenced by anatomical development and perfusion. Maternal cardiovascular changes contribute to uteroplacental perfusion; however, they have not yet been investigated in relation to fetal growth or BW. Our aim was to explore the relationship between maternal cardiovascular adaptation, fetal growth and BW in healthy pregnancies.
  
  
  METHODS
  This was a longitudinal prospective study of women planning to conceive a pregnancy. Maternal cardiac output (CO), cardiac index (CI), pulse-wave velocity, aortic augmentation index, central blood pressure and peripheral vascular resistance were assessed prior to pregnancy and at 6, 23 and 33 weeks' gestation. Fetal growth was assessed using serial ultrasound measurements of biometry.
  
  
  RESULTS
  In total, 143 women volunteered to participate and were eligible for study inclusion. A total of 101 women conceived within 18 months and there were 64 live births with normal pregnancy outcome. There were positive correlations between BW and the pregnancy-induced changes in CO (ρ = 0.4, P = 0.004), CI (ρ = 0.3, P = 0.02) and peripheral vascular resistance (ρ = 0.3, P = 0.02). There were significant associations between second-to-third-trimester fetal weight gain and the prepregnancy-to-second-trimester increase in CO (Δ, 0.8 ± 1.2 L/min; ρ = 0.3, P = 0.02) and CI (Δ, 0.4 ± 0.6 L/min/m2; ρ = 0.3, P = 0.04) and reduction in aortic augmentation index (Δ, -10 ± 9%; ρ = -0.3, P = 0.04).
  
  
  CONCLUSIONS
  In healthy pregnancy, incremental changes in maternal CO in early pregnancy are associated with third-trimester fetal growth and BW. It is plausible that this association is causative as the changes predate third-trimester fetal growth and eventual BW. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
authors.affiliation: Fetal Medicine Department, Rosie Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: A A
authors.initials: AA
authors.lastname: Mahendru
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK.
authors.forename: F L
authors.initials: FL
authors.lastname: Foo
authors.affiliation: Experimental Medicine and Immunotherapeutics, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: C M
authors.initials: CM
authors.lastname: McEniery
authors.affiliation: Fetal Medicine Department, Rosie Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: T R
authors.initials: TR
authors.lastname: Everett
authors.affiliation: Experimental Medicine and Immunotherapeutics, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: I B
authors.initials: IB
authors.lastname: Wilkinson
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK.|Department of Development and Regeneration, KU Leuven, Leuven, Belgium.
authors.forename: C C
authors.identifier: http://orcid.org/0000-0002-2104-5561
authors.initials: CC
authors.lastname: Lees
mesh_terms: D000328:Adult; D001724:Birth Weight; D001794:Blood Pressure; D002302:Cardiac Output / Q000502:physiology*; D005260:Female; D047109:Fetal Development; D006801:Humans; D008137:Longitudinal Studies; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies
keywords: birth weight; cardiac output; hemodynamics; pregnancy; vascular resistance