Irregular Menstrual Periods

One of the hallmark signs of PCOS is irregular periods. Women with PCOS commonly have periods that are much further apart than the standard 28 days. It is not uncommon for these women to go several months between menstrual periods, or even have no periods at all.

When menstrual periods are widely separated, it is called oligomenorrhea. When a woman goes six months without a period it is called amenorrhea.

In order to understand what causes women with PCOS to have irregular periods we need to establish the association between the ovary and the uterus. The ovary produces the hormones (estrogen and progesterone) which are responsible for developing the inside lining of the uterus - called the endometrium. It is the job of the endometrium to respond to these hormones in a fashion that will allow for a pregnancy to develop within the uterus if fertilization of an egg occurs. In order for the endometrium to respond correctly to the ovarian hormones the ovary must produce these hormones in a very organized fashion. The very important process of ovulation maintains this organization.

The ovaries of women with PCOS do not ovulate (release an egg) on a regular basis. Therefore, the hormones produced by these ovaries are not made in the organized fashion that the endometrium requires. The result of this disorganized hormone production is seen by the woman with PCOS as irregular menstrual periods. Commonly, when the woman with PCOS has a rare period they can be very heavy.

It is important to understand that not all women with irregular periods have PCOS. There are MANY causes for irregular periods, and women with irregular menstrual periods should be evaluated by a physician to determine the cause. It also important to remember that not all women with irregular ovulation have PCOS, and not all patients with PCOS have irregular periods. Many women who think they have "regular" menstrual bleeding or periods actually are not ovulating regularly. Hence, a close evaluation of the patients ovulation should be done in women who think they have "regular cycles" but have other signs of PCOS, such as hirsutism.