 [ Symptoms ] 57 yo male hbp on linisopril 20mg running fever bp is 14090 not going down should take another bp pill [ Disease ] well most birth control pills work primarily by stopping you from ovulating so that even if a sperm finds its way into the fallopian tube there will not any egg to fertilize birth control pills cause other subtle reproductive tissue changes that decrease the risk of pregnancy as well  this means when you are on the pill you do not have any fertile days  the way you do when you are ovulating taken correctly birth control pills are 99 9 effective in preventing pregnancy however the pill does not protect you from contracting a sexually transmitted disease so please always practice safe sex by using a condom i hope this answers your question