Some women because of a hormonal imbalance are unable to develop eggs in each month. An ultrasound picture of their ovaries often shows a number of small, immature eggs developing at different rates. It may also be difficult for the ovaries to develop an egg to the point of ovulation. The appearance of small cysts on the ovaries in combination with some clinical signs ( irregular periods, hirsuitism, acne, obesity) is given the term polycystic ovarian syndrome, or PCOS. Almost always the cystic eggs disappear when the next period comes. The irregular growth of eggs in women with PCOS results in irregular and usually infrequent periods. Some women with PCOS may tend to be overweight and troubled with acne and hirsutism (excess hair growth).