emergency contraception
"This medication did not work for me, but my husband and I are happy I be expecting TWINS!  I went off birth control in early September with a plan to use condoms. We ended up not using any protection at a time when I thought I was ovulating so I took Plan B within about 12 hours. I had what I thought was my period about five days early and assumed it was due to taking the Plan B. Six weeks later, I found out I'm pregnant!  I think this didn't work for me because I was ovulating and must have already had an egg available that was fertilized before I took the medication."