Depending on your current routine for pumping and the type of breast pump you are using, there are adjustments you can make to ensure an adequate milk supply.
Mothers obtain more milk in less time when they use a rental hospital-grade breast pump, and research has shown that it is important to use a double collection kit, which allows a mother to pump both breasts at the same time. Properly fitted breast shields (also be called breast cups or flanges) and other pump accessories can also make a difference.
A full-term newborn breastfeeds at least eight times in 24 hours, although the average is closer to 10 times. When pumping you need to mimic this pattern by pumping at least eight times a day. It also helps to use some hands-on techniques, such as the ones used in the Stanford University School of Medicine video, Maximizing Milk Production with Hands On Pumping (http://newborns.stanford.edu/Breastfeeding/MaxProduction.html).
Research has also found that “kangaroo care” (aka skin-to-skin contact) with one or more babies helps increase the amount obtained when pumping. The skin-to-skin contact releases hormones that help the breasts to gear up for greater milk production.
Some mothers find power pumping techniques can help too. For instance, during one or two hours of the day pump for 10 minutes, stop and rest for 10 minutes, pump for 10 minutes, stop and rest 10 minutes, pump for 10 minutes (and repeat once more if you have the time). This “cluster-pumping” hour counts for just one of the eight or more daily pumping sessions, but it could boost milk production.
If there is a lactation consultant for the NICU or hospital where your babies are, ask to see her and ask for personalized help with your pumping options. See (Erin, insert Breastfeeding.com page info re: local/area BF support, e.g. IBCLCs, etc).