A breast pump mimics a baby sucking at the breast. So, yes, using a breast pump will help to burn calories. If you are using a pump to replace breastfeeding, you have to be diligent in pumping frequently enough. Many moms use a breast pump when they are away from their babies for more than several hours or when they are at work.
What I would like to address is pumping instead of breastfeeding.
It is becoming a trend for women to pump and feed their babies from a bottle. While it is important for the baby to get the breastmilk no matter what, there are some things that these moms and babies may lose out on. First and foremost, the more a baby breast feeds, the better the mom’s milk supply typically is. No breast pump out there will strip a breast of milk better than an infant can. The other downfall of this trend is that it is very time consuming. It can take 15-30 minutes to pump, an additional 10-30 minutes to bottle feed and then the time it takes to clean bottles and all pumping equipment. With all of this time spent, what usually happens is that pumping times start to space out further and further throughout the day and night causing a decrease in milk supply.
When you breastfeed, you will burn calories more effectively because you will just naturally put your baby on the breast more throughout the day than being hooked up to a pump. You will also find that great skin to skin connection with your baby that is irreplaceable. Also, when a baby breast feeds, the breast milk sprays into the baby’s oropharynx, helping to clear out the mucus and reduce risk of infection of the upper respiratory tract.