Longer Menstrual Cycles: Causes & What to Expect

Question
Hi Dr. Rappaport,

I am 27 with no children, and the first day of my last period was 35 days ago (but I am on the brink of getting my period today).

All my life, my menstrual cycle has always been quite regular - always between 28-31 days.  However, my last two menstrual cycles (including the current one, as you may have noticed) have been considerably longer - about 35 or 36 days.  I am not sexually active, so I know that I am not pregnant.  I have not undergone any other diet or life changes that I can think of in the last ten months.  What could possibly be causing my menstrual cycle to suddenly become so much longer?  Would there be any reason for concern?

Thank you!
Emily

Answer
A cycle is considered normal if it is 21-35 days (from the start of one period to the start of the next period). There are many factors that can change the length of a cycle. YOu may have some imbalance of estrogen or progesterone, etc. Normally, when a cycle is outside the range of normal values, we usually regulate the cycle using birth control pills for a few months. I would suggest that you discuss it with your gynecologist.