Hallow Dear, Yes, missing a period in a girl who used to menstruate regularly and has a history of sexual exposure should be suspected due to pregnancy unless and until proved otherwise. Withdrawal method is very unsafe method. Though the penis is withdrawn from the vagina before semen ejaculation, pre-ejaculatory secretions are always discharged into the vagina unknowingly. These secretions do contain some sperms which can cause pregnancy. To remove the dilemma, I would advise you to perform pregnancy test on your overnight first morning urine sample about a week after missed period. Earlier, these tests may report false negative. Alternatively, you may get Beta hCG test done which is very sensitive and gives reliable reports even few days before missing a period. To avoid such stressful situations in future, please adopt reliable birth control methods like condom, birth control pills or intrauterine device. I am sure, this provides you solution for your dilemma. Dr. Nishikant Shrotri