Are your babies getting any other supplements besides your expressed milk? With that kid of gain I am thinking babies can be getting to the breast exclusively pretty soon, here, no?
Ok, so I cannot remember where I saw the "store in the fridge" tip. But here is what is suggested in The Womanly Art of Breastfeeding, and actually it may not be appropriate due to your babies being premature, but you will have to decide for yourself. Here is what it says:If I put the pump parts in the fridge how often would I have to wash them?
"Unless you're pumping for a premature or ill baby, just rinse the flanges and set them aside for the next pumping, washing them at the end of the day. Hot, soapy water is fine for healthy, full term babies. If your baby is hospitalized, follow the hospital guidelines for expressing and storing your milk." *
*from The Womanly Art of Breastfeeding, 8th Edition, page 301.
The cold of the fridge would retard any bacterial growth, so I imagine that is where that idea comes from. But because your babies were premature and are just out of the hospital, this time saver may not be appropriate after all. But your babies sound like they are doing awesome and are no longer in the hospital, and are now (just barely) 37 weeks aka ‘term” right? So, I just do not know!
I do think you could pump a little less often maybe? You are pumping almost twice the recommended amount for a newborn who is not nursing at all. Your babies ARE nursing-right? so I do not understand why you need to pump 15 or 16 times a day as well. You want to be careful to not overstress yourself and also be very careful about pump injury.