In most cases, early miscarriages are due to a chromosomal abnormality. A
spontaneous abortion (proper name for a miscarriage) is not at all due to anything the mother does, barring drugs, alcohol or other dangerous activities. If the fetus is a healthy, viable child, your body wouldn't naturally abort unless you have an incompetent cervix. All you can do is take it as easy as possible and hope for the best.