"Most miscarriages (about 60%) occur randomly when an embryo receives an abnormal number of chromosomes during fertilization. This type of genetic problem happens by chance; there is no medical condition that causes it. However, it becomes more common in women of increased reproductive age. Are there other genetic problems associated with repeated miscarriages? In a small number of couples who have repeated miscarriages, one partner has a chromosome in which a piece is transferred to another chromosome. This is called a translocation. People who have a translocation usually do not have any physical signs or symptoms, but some of their eggs or sperm will have abnormal chromosomes. If an embryo gets too much or too little genetic material, it often leads to a miscarriage."