Why would my period last for only 1 day?

Many reasons: It's difficult to say without a thorough history & physical exam, but check a urine pregnancy test. If that is negative, then this is most likely a hormonal "blip." of course if it is positive, see your ob! best of luck.

Length varies: Women have different lengths of menstruation. Sometimes stress, weight, excercise, oral contraception and many more triggers may affect how much, for how long and when you menstruate. If a one day menses is irregular for you it would be best to see an obgyn for evaluation. My office is in boca if you are interested in following up. http://www.obgynspecialistsbocaraton.com/drschmidt.html.