Even though PMS is common, doctors don’t know exactly what causes it. It probably has to do with changes in your body chemistry around the time of your period.
Some conditions affect PMS, but don’t cause it. PMS can be brought on, or can get worse if you:
- Smoke
- Are under lots of stress
- Don’t exercise
- Don’t sleep enough
- Drink too much alcohol or eat too much salt, red meat, or sugar
- Are depressed
Women with other health problems may find that those problems get worse before their period. Some of those are migraine headaches, asthma, and allergies.