GynoFiles

The reader asked if passing a decidual cast means she's not a virgin. In gynecologic circles 'sexual debut' means starting to have intercource (sex!). Penetrative sex for the first time produces tears in the hymen, and they usually have specific configuration but not always. Tampons produce some stretching and or tearing of the hymen and reportedly so can some physical activity. Not being able to properly insert your tampon may mean the hymen is very tight or has a bit of extra tissue, without any thing being really wrong. Just the menstrual bleeding or even passing clots on your period, or even passing a decidual cast  shouldn't be able to tear the hymen. Passing a decidual cast might cause tearing particularly in a young women, but it wouldn't be common.

Small band of tissue that is the torn piece of hymen Closer view of the hymen band The torn piece of hymen can form a pouch as well as a band