The relationship between placental characteristics and birthweight discordance in different types of selective intrauterine growth restriction in monochorionic diamniotic twins: A single-center 7 year cohort study

Objective To clarify the relationships between placental characteristics and birthweight discordance in three types of selective intrauterine growth restriction (sIUGR) in monochorionic diamniotic twins. Methods A retrospective cohort study was conducted between April 2013 and April 2020. Associations between placental characteristics and birthweight discordance were evaluated through multiple linear regression analyses with two models for each sIUGR type. Model A was adjusted for gestational age, Model B additionally adjusted for the impact of placental characteristics interacted. Results In cases of type I sIUGR, birthweight discordance ratio was positively associated with placental territory discordance ratio [(β=0.181,95%CI(0.072,0.290),P＜0.05),(β=0.239 ,95%CI(0.125, 0.353),P＜0.05)] under both Model A and Model B. In type II sIUGR [(β=-0.012,95%CI(-0.020, -0.004),P＜0.05), (β=-0.010,95%CI (-0.018, -0.002),P＜0.05)] and type III sIUGR [(β=-0.011,95%CI (-0.021, -0.001), P＜0.05),(β=-0.012,95%CI(-0.022, -0.003),P＜0.05)], birthweight discordance ratio was negatively associated with the total diameter of all the anastomoses as calculated with both Model A and Model B. Conclusion Birthweight discordance is primarily related to placental territory discordance in type I sIUGR, whereas vascular anastomoses play important roles for growth-restricted fetal compensation in type II and III sIUGR. This article is protected by copyright. All rights reserved.