I had insufficient breastmilk production and had to supplement with formula. My lactation consultant recommended that I rent the Medela Symphony hospital grade pump, even though I told her I was using my own Medela Pump In Style breast pump. She said the Pump In Style is good for expressing established milk and the Symphony is made to help establish the milk supply.
With the Pump In Style, I was getting a total of .6 of an ounce every 3 hours (end of baby's first week). I tried all of the lactation consultant's recommendations and got it up to 1 ounce total per double pumping by week 3. From the first time I used the Symphony, I had 2 ounces total per double pumping (less if it was less than 3 hours since the last feed/pump).
Note that the rental price was $80/month + $40 kit that is available on Amazon, but you can look into having your medical insurance or FSA cover some or all of the costs. Note - if you have the Medela breast shields, connectors, membranes, and bottles, you will only need to get the special tubing and connectors for the Symphony.
Other recommendations from the lactation consultant:
-Always double pump
-You must establish your breast milk volume in the first four weeks
-Take Motherlove More Milk Plus supplement (she said Mother's Milk tea doesn't have sufficient quantities of the needed ingredients, but also said there's no empirical evidence that this improves your milk supply). It's more than ten dollars cheaper on Amazon than at Whole Foods.
-Nurse every 2 to 3 hours (I tried this but the first few weeks she's so sleepy that she just won't keep at it) and pump afterwards to make sure breasts are emptied
-Get the baby undressed to diapers, skin to skin, and use cross cradle position (she showed videos from Dr. Jack Newman's website of proper hold, proper latch, and how to tell if the baby is swallowing).
Be kind to yourself and either get one of the bras made for hands free breast pumping or take one of your old bras and cut little holes in the center of the cups. You can then thread the shield through the bra and attach the rest and regain the use of your hands. =)
This really helped us!