Longitudinal Doppler references for monochorionic twins and comparison with singletons

Autoři: Daniela Casati aff001;  Marcella Pellegrino aff002;  Ivan Cortinovis aff003;  Elena Spada aff004;  Mariano Lanna aff001;  Stefano Faiola aff001;  Irene Cetin aff002;  Maria Angela Rustico aff001
Působiště autorů: Fetal Therapy Unit 'Umberto Nicolini', Vittore Buzzi Children's Hospital, University of Milan, Milan, Italy aff001;  Department of Obstetrics and Gynecology, Vittore Buzzi Children's Hospital, University of Milan, Milan, Italy aff002;  Laboratory G.A. Maccacaro, Department of Clinical Sciences and Community Health, University of Milan Milan, Italy aff003;  Neonatal Unit, University of Turin, City of Health and Science of Turin, Turin, Italy aff004
Vyšlo v časopise: PLoS ONE 14(12)
Kategorie: Research Article
doi: https://doi.org/10.1371/journal.pone.0226090



To construct monochorionic (MC) twin-specific longitudinal Doppler references for umbilical artery pulsatility index (UA-PI), middle cerebral artery (MCA) PI and peak systolic velocity (PSV) and ductus venosus (DV) PI derived from a strictly selected cohort of uncomplicated MC twins. The secondary aim of the study was to compare our findings with singleton reference charts.


A retrospective evaluation was made of all consecutive uncomplicated MC twin pregnancies referred to our Unit from 2010 to 2018. Fortnightly serial examinations were performed of UA-PI, MCA-PI, MCA-PSV and DV-PI, according with the clinical protocol, from 20 to 37 weeks of gestation. We included cases with at least four ultrasound examinations, delivery at our hospital and complete neonatal follow up. A two-step method was used to trace the estimated centile curves: estimation of the median was performed with appropriate fractional polynomials by a multilevel model and estimation of the external centiles through the residuals (quantile regression). The comparison with singletons was made by plotting the references derived from the present study on the referred charts commonly used for singletons.


The study group comprised 150 uncomplicated MC twin pairs. Estimated centiles (3rd, 5th, 10th, 50th, 90th, 95th, 97th) of UA-PI, MCA-PI, MCA-PSV and DV-PI in function of the gestational age are presented. The comparison with singletons showed substantial differences, with higher UA-PI and lower MCA-PI and PSV median values in MC twins. Median DV PI values were similar to the values for singletons, while the upper centiles were higher in MC twins.


This study sets out MC twin-specific longitudinal references for UA-PI, MCA-PI, MCA-PSV and DV-PI derived from the largest series of uncomplicated MC twin pregnancies presently available. The comparison with singleton reference values underscores the deviation from physiology that is intrinsic to these unique pregnancies and supports the need for MC twin-specific charts.

Klíčová slova:

Cerebral arteries – Fetuses – Charts – Labor and delivery – Neonates – Pregnancy – Twins – Umbilical arteries


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