How Effective Are Condoms? How well a condom works depends a lot on if you use it the right way. A woman can get pregnant even if she or her partner uses a condom. When used properly, male condoms are about 98% effective. This means that in a year, 2 out of every 100 women whose partners always use condoms correctly will get pregnant. That number rises to 18 out of every 100 women whose partners don’t use the condom