Late Periods and Endometriosis

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Affecting approximately five million women in North American each year, endometriosis is a chronic disease whose origin is not completely understood. Another aspect of the condition that is not completely understood is the link between late periods and endometriosis. The reporting of late or missed periods, without being pregnant, is fairly common in women suffering from endometriosis. Periods can be a few days late, weeks late, or for some, months will pass with no cycle at all. There are several theories as to why this occurs. These include hormone levels, adhesions and scar tissue, and factors that may affect ovulation.


Normal endometrial tissue lines the uterine wall and secretes a group of hormones called prostaglandins. These hormones are found in nearly all tissues of the human body, and are required for a normal menstrual cycle and pregnancy, as well as other bodily processes. With endometriosis, endometrial cells grow in places outside the uterus. However, they continue to function as they would if inside the uterus, releasing hormones, causing bleeding, etc.

One theory believes that late periods and endometriosis are linked due to the amount of endometrial tissue outside the uterus versus inside. If there is a larger amount of tissue outside the uterus than inside, the hormones are released into the abdomen instead of the womb. The trigger for the body to begin the menstruation cycle is insufficient and ineffective. This can result in late or missed periods.

Adhesions and Scar Tissue

During her normal monthly cycle, a woman’s ovaries produce hormones to stimulate the wall of the uterus to prepare for pregnancy. The cells of the uterine wall (endometrial cells) multiply, thicken, and await the arrival of a fertilized egg. If no egg arrives and attaches, these cells are flushed from the body, as evident by the menstrual bleeding.

However, when endometriosis is present, these same cells are found outside the uterus and, just as they do on the uterine wall, they also thicken and multiple. In addition, these cells attempt to flush from the body through bleeding, but with no way for this blood to leave the body, resulting in the cells healing, and repeating the cycle over and over each month. This repeated multiplying, swelling, bleeding, and healing can often lead to scar tissue, adhesions, or fusion of the various tissues of reproductive organs and surrounding structures – fallopian tubes, ovaries, and supportive structures of the uterus inside the pelvis. The scar tissues, adhesions, and tissue fusion can often result in distortion of the actual anatomy of the reproductive organs, affecting ovulation, menstrual cycles, and fertility.


To date, research has not offered a determining cause for endometriosis. With no known cause, knowing who’s at risk becomes more difficult. A history of unexplained late or missed periods should not be left undiagnosed, even in the absence of other symptoms. It is possible for the symptoms for endometriosis to worsen over time. Seek medical advice and talk to a health care provider regularly.


Endometriosis Association.