Extremely sorry to know about this. Cause cannot be always found out. Sometimes fetal genetic defects may lead to intrauterine fetal death. Fetal autopsy may give a clue in some cases.

Really it's difficult mentally and physically to go through such process... Have a proper talk with you fertility expert.. She can better advice you as she knows your history

I am sorry to hear about your pregnancy loss. It could happen due to problems in the baby, placenta or a number of other reasons. In the absence of blood tests on you, and examination of the baby after it was delivered, it is not possible to determine the reason for the late miscarriage. Sometimes, even after doing all tests, we are unable to find a reason. Because it has happened once, it does not necessarily mean that it will happen again in the future, if you conceive. Usually, but not always, miscarriages happen as an isolated episode, without recurrence in future. Wish you all the best for the future.