Condom ripped 2,3mins after starting sex 10mins after gf took planb one step can it work?she also has feeling of period her period due date is 28nov

Strong chance: Plan B One-Step is up to 89 % effective when taken within 72 hours (3 days) after unprotected sex. It can reduce chance of pregnancy by up to 95% if used within 24 hours. It continues to reduce the risk of pregnancy up to 120 hours (5 days) after unprotected sex, but is less effective as time passes.

Plan B: With essentially "unprotected sex" (broken condom) Plan B will work most of the time. A feeling of a "period beginning" can be due to ovulation, since estrogen levels fall just before the release of the egg. Get a serum pregnancy test from a healthcare provider if no period has started by December 2-4. If is very accurate and if negative, she is not pregnant.