Hi, and thanks for your medical question on eHealth forum!
A miscarriage can be very traumatic and I can understand your apprehensions. Each pregnancy behaves separately. Also some causes of miscarriage are related to that pregnancy alone. Some causes tend to recur and you must be careful about these.
Generally first trimester abortions or abortions occurring in first three months are due to fetal abnormality, genetic causes, Rh blood group incompatibility and low progesterone hormone. Infection of the uterus, endometriosis, fibroids, etc. are some other causes for early abortion.
You need to consult your gynecologist (consult another one if need be) and run some tests to rule out these causes. Hope this helps. Take care!