Note the extremely crucial "typically" part. Depending on age health genetics fitness diet etc, periods may be more or less regular, more or less frequent, mor

Note the extremely crucial "typically" part. Depending on age health genetics fitness diet etc, periods may be more or less regular, more or less frequent, more or less obvious in various ways. Similarly absence of period may or may not be noticed, and may or may not in itself be various degree of normal. Person may it may not have access money and ability to use a pregnancy test. Pregnancy test may have certain range of confidence and accuracy. Person may need any amount of time to make a decision and set up logistics. (That is assuming we are even contemplating ordering a woman to sacrifice her own body and health for somebody else, which I am not. But figured you should have specific answer to your specific question :)