How do you know if you really do have a low supply?

skibunny59

Sorry if this is a silly question.  According to DD's pediatrician, since I don't feel engorged all the time and DD didn't gain much weight at her last appointment, it must be because of low supply.  Obviously, I don't really trust her since I know that you don't have to feel engorged all the time to be producing enough.  DD used to fall asleep and hang out at my breast very frequently.  The last couple of days she has been nursing very well and I can hear her swallowing.  Also, I am able to pump almost an ounce in each breast right after I'm done feeding her.  Especially since she didn't gain weight well, I just want to make sure she really is getting enough from me.  I was supplementing because the pedi told me I had to but now I'm wondering if it's really necessary.  We are also seeing a new pedi on Monday.