In the battle against breast cancer, proactive care is a key weapon. While only a mammogram can detect tumors before they can be felt, 40 percent of breast cancer diagnoses begin with women feeling a lump. Monthly self-exams keep you familiar with your breasts so you can identify changes more easily.

Here are three ways you can do an at-home breast checkup:

1. While Showering
Move the pads of your fingers around your breast in circular motions. Work your way from the outside of your breast to the center, making sure to cover the entire breast all the way to the armpit area. Look for any lumps, thicker areas, or hardening knots.

2. While Looking in a Mirror
Stand with your arms by your sides, and study your breasts. Then, lift your arms over your head and check for swelling, dimpling, or differences in the nipples or contour. Finally, press your palms to your hips to contract your pectoral muscles and look for changes such as dimpled or puckered tissue.

3. While Lying Down
To check your right breast, lie with a pillow, folded towel, or other support beneath that shoulder. Tuck your right hand under your head. With your left hand, feel your entire breast and armpit area, using circular motions. Vary how firmly you press on the tissue, and squeeze the nipple to see whether it produces discharge. Then, switch sides.

If you discover a lump, don’t panic! Eight in 10 lumps are not cancerous. But to take a closer look, schedule an appointment with your doctor right away. Don’t be afraid to ask all the questions you have — before or after discovering changes.

Breast cancer is the most prevalent type of cancer among women, but luckily, the number of lives this disease takes is steadily decreasing due to early detection and improved treatments. When you become an agent of your own well-being, you’ll better protect yourself.