What causes infertility in women?

In most cases, infertility in women is caused by ovulation problems. When ovulation does not occur—or does not occur properly—there are no eggs or only damaged eggs to be fertilized. Irregular or absent menstrual periods are two signs that a woman many have ovulation problems. In other cases, there may be few if any noticeable symptoms. Other problems include blocked fallopian tubes, uterine fibroids, abnormalities of the uterus, or diseases like endometriosis.