My last period was oct 12 to 17. since then i have not had period. i am 43 and not sexually active. cycle length 26 days. once had period 78 days late. what is causing missed period?

Some thoughts...: In a woman with regular periods, some causes of a late period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (like birth control pills), hormonal imbalances, etc… Seeing her Ob-Gyn doctor is a good idea if symptoms are persistent, recurring, or worrisome.