Well, we have been asked this question many times, and there is a lot of information and mis-information out there. There are 2 types of breast pumps - single user and multiple user (hospital grade pumps or rental pumps).
Hospital grade pumps are sealed. It prevents any viruses from being transferred between users and should be wiped with a disinfectant cleaner after each patient. These are meant to be used over and over, sometimes many times in a day. They have a much sturdier motor and will generally last much longer. As long as each user has their own collection kit, or a hospital sterilized one the risk of transfer of viruses and or bacteria is very small.
The bigger issue is all of the pumps you can find on used sites such as Craigslist and EBay. First of all, many of them are old, will be void of warranty and the collection kits might contain BPA which was banned in Canadian baby products in 2008. Second of all, many people feel they are being thrifty or helpful by selling or lending their pumps to a friend. Health Canada designates (not the breast pump companies!) these items as single user. You can't return these to the stores if they are broken or if you don't like it. You must deal directly with the manufacturer or distributor for any warranty issues. I have always looked at it this way. Would you share your diabetes monitor? It is essentially the same thing, as breast milk is considered a body fluid on the same level as blood. Plus would you really want to put your newborn sweet baby at risk?
There are 2 types of electric breast pumps out there - closed systems and open systems. If you are for sure planning to buy a used pump, make sure you buy one that uses a closed system. A closed system means that the milk in the collection kits stays contained and there is no way to travel into the tubing to get into the pump motor. No matter which type you buy make sure you buy a completely new collection kit for the milk. This is the most at risk part of the pump. You can purchase them at any rental pump location or at most of the places that sell new breast pumps.
There is also the main question you need to ask yourself about why you are buying a pump. Are you planning to breast feed your baby or feed your baby breast milk? The answer to that will give you a good insight as to whether you will even need an electric pump. For most moms who are planning to breastfeed and give the occasional bottle, a hand pump will suffice. You might find your baby won't take a bottle and prefers the breast or you might have the best intention of breast feeding and run into complications you didn't know you would face. Either way you don't need to invest in a pump until after the baby comes. Do all of your searches and have an idea of what kind of pump you think you will want; and when your beautiful sweet baby comes along you will have a good idea of your breastfeeding rhythm. Every breastfeeding "couple" has its own rhythm (Nancy Morbacher - The 7 Natural Laws of Breastfeeding) and you will find yours!
