Why do women have tender breasts before their periods and also when they're pregnant? And how do you know if it's due to pregnancy or a period?
- Charlisse*

When women get their periods or are pregnant, their hormones change. And, even though periods and pregnancy are different, the hormone changes that go with them can cause lots of similar issues — like breast tenderness, acne, and mood changes. So, if you've had sex, it can be hard to know if things like breast tenderness are caused by a period or pregnancy.

If you think you might be pregnant, take a home pregnancy test, see your doctor, or visit a health clinic like Planned Parenthood. (If you take a home pregnancy test and it's positive, follow up with a visit to a doctor or health clinic.)

Reviewed by: Larissa Hirsch, MD
Date reviewed: July 2010

* Names have been changed to protect user privacy.