If cramping is not followed by vaginal bleeding ,then there is nothing to be worried about. But you can never be sure what will happen in the future. If the reasons that provoked the last miscarriage are still present (or occur again), then there are big chances for another miscarriage. When a miscarriage starts, very little can be done. The most common reasons for early miscarriage are: genetic causes, radiation, mutagenic substances including medicines, viral infections during the pregnancy, inflammatory damaged uterus, hormonal etc.