Uterine artery impedance during the first eight postpartum weeks.
The aim of this study was to construct reference ranges for the uterine artery (UtA) mean pulsatility (PI) and resistance (RI) indices from 1-8 weeks postpartum. A prospective, cross-sectional, and observational study was performed with 320 healthy women from week 1 through week 8 postpartum. UtAs were examined transvaginally using colour and pulsed Doppler imaging, and the means of the right and left values of the PI and RI, as well as the presence or absence of a bilateral protodiastolic notch, were recorded. The 5(th), 50(th) and 95(th) reference percentile curves for the UtA-PI and UtA-RI were derived using regression models. The adjusted reference intervals uncovered a convergence trend at the week 8 time-point, although impedance was lower at the week 1 time-point in multiparous women compared with primiparous women. The notching prevalence was 22.5% (9/40) at week 1 and 95.0% (38/40) at week 8. The study revealed consistent evidence of a progressive increase of postpartum uterine impedance and provided new average UtA-PI and UtA-RI reference charts for weeks 1 through 8. Multiparity does not change the trend but does impart a lower rate of increase, likely as a consequence of previous vascular structural and functional differences.
1] Department of Experimental Biology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal [2] IBMC-Instituto de Biologia Molecular e Celular, 4150-180 Porto, Portugal [3] Hospital Centre of Porto EPE, Department of Women and Reproductive Medicine, Largo Prof. Abel Salazar, 4099-001 Porto, Portugal.
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Guedes-Martins
1] Department of Mathematics, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal [2] CMUP-Centre of Mathematics, University of Porto, 4169-007 Porto, Portugal.
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Gaio
1] Department of Experimental Biology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal [2] Hospital Centre of Porto EPE, Department of Women and Reproductive Medicine, Largo Prof. Abel Salazar, 4099-001 Porto, Portugal.
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Saraiva
Hospital Centre of Porto EPE, Department of Women and Reproductive Medicine, Largo Prof. Abel Salazar, 4099-001 Porto, Portugal.
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Cunha
Department of Cardiology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal.
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Macedo
1] Department of Experimental Biology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal [2] IBMC-Instituto de Biologia Molecular e Celular, 4150-180 Porto, Portugal [3] Obstetrics-Gynecology, Hospital-CUF Porto, 4100-180 Porto, Portugal.
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Almeida
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D049590:Postpartum Period / Q000502:physiology*; D011673:Pulsatile Flow; D012307:Risk Factors; D013997:Time Factors; D014463:Ultrasonography; D055988:Uterine Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D014655:Vascular Resistance; D055815:Young Adult