Pumping and letdown question

nsimoncavage

My son is almost 5 months old and EBF.  Lately, my afternoon pumping session has been taking increasingly longer.  I am still producing at normal levels, but it seems I am having letdown issues.  After the initial letdown, milk only flows for 10 or so minutes...and I have to increase suction (at an uncomfortable level) in order to stimulate letdown again.  Is this normal?  Anyone have any advice for a more free-flowing pumping session?