MRI features of pseudomyomous contractions in the myometrium during pregnancy

QIN Dan; PAN Zhibin; WANG Ping; GUO Yue; CHEN Yukun; TENG Jiaqi

doi:10.3969/j.issn.2097-1753.2025.05.016

Abstract：Objective To explore the MRI manifestations of pseudomyomatous uterine contractions in the myometrium during pregnancy,advance our understanding of related signs,and help prevent misdiagnosis and mistreatment.Methods A retrospective analysis was conducted of 106 patients with pseudomyxomatous uterine contractions during pregnancy at Cangzhou Central Hospital between January 2018 and June 2022.The site of placental attachment,incidences of cesarean scar pregnancy,placental implantation,placental hypoplasia,placenta praevia,and the site,size and signals of pseudomyxomatous uterine contractions were recorded.Results The percentage of mid-term pregnancies was the highest(79.24％).Ninety-six cases(90.57％)had a second pregnancy or more.88 cases whose sites of placental attachment were purely anterior or close to the anterior wall was the largest(83.02％),and the percentage of scar pregnancies and non-scar ones was similar.There were 70(66.04％)cases of non-placental implantation.Contractions were located at the site or on the edge of placental attachment in 90 cases(84.91％).The pseudomyomatous uterine contractions in the myometrium mostly occurred as dome-shaped and spindle-shaped changes on imaging in 92 cases(86.79％).A statistically significant difference was observed in myometrial pseudomyomatous uterine contractions between the first and second trimesters of pregnancy.(x2=9.113,P=0.003).The incidence of pseudomyomatous uterine contractions in the myometrium was significantly higher in early pregnancy than in mid-term pregnancy among cases complicated with placental hypoplasia or placenta previa(x2=3.962,P=0.047).No statistically significant differences were observed in myometrial pseudomyomatous uterine contractions between the first and second trimesters(all P＞0.05).Conclusion In the course of early and mid-term pregnancy,the possibility of uterine pseudomyomatous uterine contractions should be taken into consideration if the myometrium shows spindle-shaped or myometrial verrucous contractions parallel to the long axis of the placenta,with or without scarred uterus and placenta implantation so as to avoid misdiagnosis of uterine myometrial pathology such as uterine fibroids or uterine adenomyosis.