Endometriosis constitutes the presence of ectopic endometrial glands and stroma outside the uterine endometrium, which is hormonally responsive and responds to pregnancy hormones as well. Decidualization is a physiologic process, where the normal endometrium readies itself for optimal accommodation of a pregnancy. A similar hormonal response can be seen with ectopic endometrium as well. As such, ovarian endometriomas and deep endometriosis implants can undergo decidualization. Overall, the progestational state of pregnancy favors an improvement in endometriosis, however, decidualization can lead to findings that can lead to increased size of endometriomas and deep infiltrative endometriosis implants, changes in imaging appearance and even complications, such as spontaneous hemoperitoneum in pregnancy. Awareness of this process can help prevent misdiagnosis of decidualized endometriomas as ovarian malignancy and recognize common imaging manifestations of hormonal effects of pregnancy on endometriosis.

中文翻译：

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妊娠子宫内膜异位症。

子宫内膜异位症构成子宫内膜外异位子宫内膜腺体和间质的存在，这是激素反应性的，对妊娠激素也有反应。蜕膜化是一个生理过程，正常子宫内膜可为妊娠的最佳适应做好准备。异位子宫内膜也可以看到类似的激素反应。因此，卵巢子宫内膜瘤和深部子宫内膜异位植入物可能会蜕膜化。总体而言，妊娠的孕期状态有利于子宫内膜异位症的改善，但是蜕膜化可导致发现结果，从而导致子宫内膜瘤和深层浸润性子宫内膜异位植入物的体积增大，影像学外观改变甚至并发症，例如妊娠中的自发性腹膜炎。