When discussing pregnancy with 35-year-olds, many forget that there are other factors that can quite strongly affect the onset or absence of pregnancy. Problems with conceiving can occur earlier than many of us expect. After all, general health affects the reproductive system. For example, polycystic ovary syndrome is the most common cause of infertility, and as a result, pregnancy does not occur with regular attempts throughout the year, according to the Mayo Clinic at fertially.com. One of the hallmarks of the disease is irregular or absent ovulation, which makes it difficult to get pregnant.