You have to understand certain facts. Whether 28 or 30 day cycle, if it is regular, usually the mid day of the cycle is the ovulation period. There is a leverage of + or - 3 days are there. So we call it as danger period for those who don't want pregnancy
. Only contact between you occurs during this 7 days chance for pregnancy is there. Even though ladies have 2 ovaries only one ovum is released in every cycle which may be from the right or left. It waits for a short period (maximum 24 hrs) to get impregnated. I think I am clear.
If pregnancy is confirmed and miscarriage
occurs - then elaborate investigations are needed for both of you.
They are Blood tests, USG, and important is Hormone analysis. some times Endometrial Biopsy
The treatment is according to the results. Consult Your Gynecologist. She will help you.