Ward Samantha, Sun Zhonghua, Maresse Sharon
Discipline of Medical Radiation Science, Curtin Medical School Curtin University Perth Western Australia 6845 Australia.
Australas J Ultrasound Med. 2024 Jun 14;27(4):200-209. doi: 10.1002/ajum.12399. eCollection 2024 Nov.
INTRODUCTION/PURPOSE: It is well-documented in the literature that the placenta migrates during pregnancy; however, studies regarding placental cord insertion (PCI) migration are scarce. This longitudinal, prospective study aimed to determine whether PCI migration is a true phenomenon, to assess whether the PCI can change classification during pregnancy and to determine the validity of PCI site documentation including follow-up of abnormal PCI.
Eighty-three participants who had first, second and third trimester ultrasound examinations at a Western Australian private imaging practice over a 12-month period between November 2021 and November 2022 were recruited. The measured distance of the lower margin of the placenta to the cervix, the distance of the PCI to the closest placental edge and the PCI classification were documented in each trimester. Data analysis was conducted to determine PCI migration rates during pregnancy and to test for association between PCI migration and maternal and placental factors.
The PCI migrated during pregnancy and the PCI classification has the potential to evolve. All identifiable PCIs that were normal in first trimester remained so throughout the pregnancy. The majority (67.6%) of cord insertions that were marginal in first trimester progressed to a normal insertion site by third trimester; 23.5% remained marginal and 8.8% evolved to a velamentous insertion. Three velamentous cord insertions were recorded in first trimester, none of which normalised-two remained velamentous during the pregnancy and one evolved to marginal in second trimester. Marginal cord insertions (MCIs) ≤10 mm from the placental edge in second trimester remained marginal in third trimester; MCIs that were >15 mm from the placental edge in second trimester normalised in third trimester.
Placental cord insertion migration is a phenomenon that occurs during pregnancy with the potential for PCI classification to evolve. Due to the association between abnormal PCI and perinatal complications, coupled with the potential for marginal cord insertion to evolve, documentation of PCI and follow-up of abnormal PCI is beneficial, particularly in cases of velamentous insertion and marginal insertion at the placental edge or in the lower uterus.
引言/目的：文献中已有充分记载，胎盘在孕期会发生迁移；然而，关于胎盘脐带插入点（PCI）迁移的研究却很稀少。这项纵向前瞻性研究旨在确定PCI迁移是否确有其事，评估孕期PCI分类是否会改变，并确定PCI位置记录的有效性，包括对异常PCI的随访。
招募了83名参与者，他们于2021年11月至2022年11月的12个月期间，在西澳大利亚一家私立影像机构接受了孕早期、孕中期和孕晚期的超声检查。记录每个孕期胎盘下缘至宫颈的测量距离、PCI至最近胎盘边缘的距离以及PCI分类。进行数据分析以确定孕期PCI迁移率，并检测PCI迁移与母体及胎盘因素之间的关联。
PCI在孕期发生迁移，且PCI分类有可能发生变化。所有在孕早期可识别的正常PCI在整个孕期均保持正常。孕早期边缘性的脐带插入点，大多数（67.6%）在孕晚期进展为正常插入点；23.5%仍为边缘性，8.8%演变为帆状插入。孕早期记录到3例帆状脐带插入，无一例恢复正常——2例在孕期持续为帆状，1例在孕中期演变为边缘性。孕中期距胎盘边缘≤10毫米的边缘性脐带插入点在孕晚期仍为边缘性；孕中期距胎盘边缘>15毫米的边缘性脐带插入点在孕晚期恢复正常。
胎盘脐带插入点迁移是孕期发生的一种现象，PCI分类有可能发生变化。由于异常PCI与围产期并发症之间存在关联，再加上边缘性脐带插入点有演变的可能，记录PCI并对异常PCI进行随访是有益的，尤其是在帆状插入以及胎盘边缘或子宫下段边缘性插入的情况下。
