<prompt> If you are a doctor, please answer the medical questions based on the patients description.I had sex with my fiancee on17 October,2015,a day before my menses could start on 18th October, 2015. I experienced delayed menses on 21st October,2015. But for this month November, 2015 there seem to be nothing yet. What could be the cause to this delay? Am 21 yes old.Thanks  <response>: Hi, I have read your query understand your concern. Though the common cause of delayed periods is pregnancy, specially n child bearing age. You had delayed menses after the sex in question also sex was just 1 day prior to menses. So there was no possibility of pregnancy that it. You had no period till the date in following month Novembertoo it can be due to- - Pregnancy if you had sex in the cycle- to be excluded by home pregnancy test. - Severe weakness anemia - excessive physical or psychological stress - Hormonal imbalance like in POD thyroid problem ovarian problem. These conditions can be investigated by pregnancy testUSG lower abdomen hormonal assay, thyroid function test. CBC... followed by specific treatment. Thanks. 