periplacental fold

例句：

1. 1.The periplacental fold is a thin layer of tissue that separates the fetus from the placenta during pregnancy.
   胎盘边缘褶是妊娠期间胎儿与胎盘之间分离的薄层组织。
2. 2.During labor, the periplacental folds may become ruptured, causing premature birth.
   在分娩过程中，胎盘边缘褶可能破裂，导致早产。
3. 3. Researchers are studying the effects of maternal stress on the development of the periplacental folds.
   研究人员正在研究母体压力对胎盘边缘褶发育的影响。