Unfortunately, miscarriages are common - 20-25% of pregnancies end in miscarriages.
This is increased when the mother is > 35 Y.O. I would recommend that you speak with your doctor. Recurrent miscarriages warranting a full workup is recommended after 3 miscarriages. But frequently, there are some initial lab tests that can be done to ensure that you do not have a treatable medical condition.