Period pain is common and a normal part of your menstrual cycle. Most people get it at some point in their lives.
It’s usually felt as painful muscle cramps in the tummy, which can spread to the back and thighs. The pain sometimes comes in intense spasms, while at other times it may be dull but more constant.
It may also vary with each period. Some periods may cause little or no discomfort, while others may be more painful.
What causes period pain?
Period pain happens when the muscular wall of the womb tightens (contracts). Mild contractions continually occur in your womb. During your period, the wall of the womb starts to contract more vigorously to help the womb lining shed as part of your period.
When the wall of the womb contracts, it compresses the blood vessels lining your womb. This temporarily cuts off the blood supply – and oxygen supply – to your womb. Without oxygen, the tissues in your womb release chemicals that trigger pain.
While your body is releasing these pain-triggering chemicals, it’s also producing other chemicals called prostaglandins. These encourage the womb muscles to contract more, further increasing the level of pain.
Period pain usually starts when your bleeding begins, although some people have pain several days before the start of their period.
The pain usually lasts 48 to 72 hours, although it can last longer. It’s usually at its worst when your bleeding is heaviest.
It’s not known why some of us have more period pain than others. It may be that some people have a build-up of prostaglandins, which means they experience stronger contractions. Less commonly, period pain can be caused by an underlying medical condition, like endometriosis – where cells that normally line the womb grow in other places, such as in the fallopian tubes and ovaries; these cells can cause intense pain when they shed.