According to the data you've provided (you've had 2 previous miscarriages), it seems that you can conceive but you have trouble keeping a pregnancy. There can be many reasons for early miscarriage (in the first trimester of pregnancy). The most common reasons are genetic causes from both the mother’s and the father’s sides. Viral infections, radiation, mutagenic drugs, and chemicals can also damage a embryo. Having a damaged or inflammatorily changed endometrium can also be a reason for miscarriage. Hormonal disorders (diabetes mellitus, hyperthyroidism, corpus luteum failure…) are rare causes of miscarriages. You can consult a gynecologist about this problem. Several investigations can be performed to identify the reason for current sterility.