First thing I shall be advising you is do not worry, do not take stress
Naturagest contains hormone progesterone
which is normally present in body.
It is found that low levels of progesterone in first trimester is associated with high chances of miscarriage
This hormone rather supports pregnancy
and prevents miscarriage.[if cause for miscarriage is low hormone level]
If cause for miscarriage is genetic changes ; miscarriage will occur and that is nature's way to prevent having chromosomal ly defective abnormal child.
So continue medication and go for subsequent scans to rule out other problems.
I hope I have answered your query. In case you have any doubt; I will be happy to help you.