Birth control isnt 100% i know

But if anyone has gotten pregnant on the nuvaring, which im sure someone has, what was the symptoms? Like normal pregnancy symptoms or was it something else? How did you find out? When did you find out? My friend thinks theres a chance because shes been cramping constantly since her last period and shes had discharge that looks kinda like glue but isnt sticky. We are very close lol and she doesnt want her man to think anything if shes not for sure. I dont know what to tell her, i dont have problems with my ring. So any ladies with advice would be appreciated. Thank you