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Updated: Apr 11, 2026

Accurate and Simple Evaluation of Vascular Anastomoses in Monochorionic Placenta using Colored Dye
Published on: September 5, 2011
Veno-venous anastomoses in twin-twin transfusion syndrome: A multicenter study
D P Zhao1, O Cambiaso2, L Otaño2
1Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
Introduction:
The aim of this study is to evaluate the prevalence of veno-venous (VV) anastomoses in a large cohort of monochorionic (MC) twin placentas with twin-twin transfusion syndrome (TTTS) compared to a control group of MC placentas without TTTS.
Methods:
All TTTS placentas not treated with fetoscopic laser surgery (TTTS group) and examined at five international fetal therapy centers were included in this study and compared with a control group of MC placentas without TTTS (non-TTTS group). MC placentas were routinely injected with colored dye. We recorded the presence of VV and arterio-arterial (AA) anastomoses.
Results:
A total of 414 MC placentas were included in this study (TTTS group, n = 106; non-TTTS group, n = 308). The prevalence of VV anastomoses was significantly higher in the TTTS group than in the non-TTTS group, 36% (38/106) and 25% (78/308), respectively (p = .04; odds ratio (OR) 1.65; 95% confidence interval (CI): 1.03-2.64). In the subgroup of MC placentas without AA anastomoses, the prevalence of VV anastomoses in the TTTS group and non-TTTS group was 32% (18/57) and 8% (2/25), respectively (p = .03; OR: 5.31; 95% CI: 1.13-24.98).
Discussion:
VV anastomoses are detected more frequently in TTTS placentas than in MC placentas without TTTS and may thus play a role in the development of TTTS.
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