thin lines or marks left on someone's skin after they have grown bigger quickly, for example on the skin of a woman who has been pregnant

She's worried about having children because she doesn't want to get stretchmarks or lose her figure. 她很为生孩子而担心，因为她不想有妊娠纹或是身材走样。

Stretch marks are a normal reaction to the skin stretching. 拉伸纹是皮肤拉伸的一种正常反应。