Problems with ovulation account for most cases of infertility in women. Without ovulation, there are no eggs to be fertilized. Some signs that a woman is not ovulating normally include irregular or absent menstrual periods.

Less common causes of fertility problems in women include:

• blocked fallopian tubes due to pelvic inflammatory disease, endometriosis, or surgery for an ectopic pregnancy
• physical problems with the uterus
• uterine fibroids

Source: The National Women's Health Information Center