How do I know if I have heavy periods?

Heavy periods, also known as heavy menstrual bleeding or HMB, are excessive menstrual blood loss during a single cycle (> 80 mL or about six tablespoons). You may have HMB if you: 

• have a menstrual flow that soaks through one or more pads or tampons every hour for several hours in a row
• need to double up on pads to control your menstrual flow
• need to change pads or tampons during the night
• have menstrual periods lasting more than seven days
• have a menstrual flow with blood clots the size of a quarter or larger

If you have any of these symptoms, talk to your GP. 

How does a hormonal IUD work to help reduce Heavy Menstrual Bleeding?

Typically, this is how your period works: 

• Every month, the lining of the uterus thickens during the first half of your menstrual cycle to prepare for ovulation.
• if ovulation takes place and the egg is not fertilized, the thickened uterine lining is shed as a menstrual flow
• on average, a woman’s menstrual flow lasts 3 to 5 days. It may be shorter or longer, depending on the woman

However, if you have HMB, Mirena can cause your menstrual bleeding to be less by thinning the lining of the uterus. In a clinical trial performed on women with heavy menstrual bleeding and treated with Mirena, almost 9 out of 10 were treated successfully ― with their blood loss reduced by more than half after six months. 

With Mirena, your heavy periods may change

In a clinical trial of one particular IUD in women with HMB, that IUD rapidly reduced heavy periods. The majority experienced:

Hormonal IUD may also affect heavy periods in other ways

In some women with heavy bleeding, the total blood loss per cycle progressively decreases with continued use. The number of spotting and bleeding days may initially increase but then decrease in the following months. Bleeding may also continue to be irregular.

You may have bleeding and spotting between menstrual periods, especially during the first 3 to 6 months. Sometimes the bleeding is heavier than usual at first. However, the bleeding usually becomes lighter than usual and may be irregular. Call your healthcare provider if the bleeding remains heavier than usual or increases after it has been light for a while.

About 2 out of 10 women stop having periods after one year of Mirena use. If you have any concerns that you may be pregnant while using IUD, do a urine pregnancy test and call your doctor. Call your GP if you do not have a period for six weeks during IUD use. When IUD is removed, your menstrual periods should return.