Abnormal menstrual cycles are one of the chief complaints many OB/Gyns hear from their patients. For some, the complaint is heavy bleeding, for others it’s lack of a period at all. Other patients come in with periods that are irregular, sometimes showing up more than once in a month or skipping months entirely. It is estimated that 1 in 5 women suffer from abnormal uterine bleeding during the reproductive years. Symptoms vary from bleeding at unexpected times, abnormal duration of flow, or abnormal amount of flow.
With all this talk about potentially being “abnormal”, it’s important to define what constitutes a “normal” menstrual cycle.
A normal menstrual cycle occurs when the lining of the uterus thickens to prepare for pregnancy. If you do not become pregnant, the lining of the uterus sheds along with blood. The normal interval between menstrual cycles (the time between the first day bleeding of one cycle to the first day of the next one) varies from 21 to 35 days, with an average of 28 days. The normal cycle length is between 2-7 days, usually averaging 3-5 days. Most women will bleed between 2-12 teaspoons per cycle. Notice that there is a pretty wide range of things that could be considered normal. Woman A may get a period every 21 days that lasts for 3 days while Woman B gets a period every 31 days that lasts for 7 days. The cycles are very dissimilar but both considered normal.
So what is abnormal?
Abnormal periods can be either too much or too little in frequency and intensity. Some women have abnormal periods where the flow seems exceptionally heavy, lasts longer than 7 days, or occurs more frequently than every 21 days. On the other hand, it may also be abnormal to have very infrequent periods- especially during times of stress (both physical and psychological) and during times of hormone transitions, such as the first 2 years after the onset of menses and for 2-3 years before the onset of menopause. Missing your period for 3 consecutive months is usually an indication that further evaluation is needed (unless you are on a type of contraception or other medication that stops your cycles).
You may hear your OB/Gyn using acronyms or phrases that you may not understand to describe abnormal periods. You may here things like:
- Abnormal Uterine Bleeding (AUB): overall term to describe any abnormal menstrual bleeding
- Heavy Menstrual Bleeding (HMB): occurs when you bleed more than 80 ml (about 3 cups) during your cycle. Typically, women will notice they need to change their super tampon or pad every one-two hours
- Heavy and Prolonged Menstrual Bleeding: bleeding is heavy and lasts more than 7 days
- Intermenstrual Bleeding: bleeding that occurs with an interval of <20 days from the prior menses
Regardless of the type of abnormal uterine bleeding you are suffering from, there are generally a set list of potential causes. These causes can be broken down into structural and nonstructural forms. Structural causes are physical abnormalities like polyps, adenomyosis (where the endometrial lining grows outside of where it normally should grow), fibroids, hyperplasia (an enlargement of the tissue) or a malignancy of some sort.
Nonstructural causes are things like blood clots or clotting disorders, ovulatory disorders like PCOS or anovulation, infection, secondary damage from other medical treatment (like chemotherapy or radiation treatment) etc.
If you suspect you may have abnormal periods, we suggest keeping a menstrual calendar, noting how long it lasted, the type of tampon/pad/cup used and how many were used in a 24-hour period. There are several apps available for most smart phones, but a written journal works just as well. Bring that journal with you to your next appointment to discuss with your OB/Gyn.