[mbsn]

These are all the pros and cons I could come up with for exclusively pumping compared to exclusively nursing. I welcome additions.

Out and about with baby:

Upside: You don't have to wear clothes or bring gear for easy or discreet nursing. If the baby needs to eat, you don't have to find somewhere to nurse, don't have to deal with your own nursing modesty or worry about anyone else's discomfort, and don't have to deal with people judging you for nursing in public. A hungry baby won't tug at your clothing.

Downside: You have to figure out how much milk to bring with you, how to carry it, how to keep it cold, and how to warm it up when baby is hungry. If the baby needs to eat, you have to deal with people judging you for bottle feeding (many assume bottle=formula). You have to work around your pumping schedule. If you need to pump on the go, you have to bring the pump and all the necessary pieces, find a place to pump, figure out how to wash/sterilize them if you need to pump more than once, and store the fresh milk.

Out and about without baby:

Upside: You don't have to work around baby's feeding schedule.

Downside: You have to work around your pumping schedule. If you need to pump on the go, you have to bring the pump and all the necessary pieces, find a place to pump, figure out how to wash/sterilize them if you need to pump more than once, and store the fresh milk.

Sleep:

Upside: Someone else can feed the baby in the middle of the night so you can sleep.

Downside: If you're home alone with the baby, you may have to pump while the baby is sleeping so you miss out on a chance to nap yourself. Bottlefeeding a baby in the middle of the night may wake you up more fully than nursing. Some women need to pump in the middle of the night to maintain their supply.

Pumping time:

Upside: Any pain is mentally associated with the pump, not the baby. You can monitor your supply. You can store surplus milk for times when your supply dips. You can pump on your schedule (within reason) rather than being tied to baby's hungry times. If you have a good supply, you may be able to extend breastmilk feeding (e.g. pump until baby is 10 months old then feed frozen milk until he/she is a year old). You may be able to do certain things while pumping that you can't do while nursing.

Downside: You may not be able to do certain things when strapped to the pump that you can do while nursing. Pumping is, in general, less efficient than nursing so you may struggle with keeping up your supply. Pumping is difficult to do discreetly in public. You have pump parts to clean and sterilize.

Feeding time:

Upside: Someone else can take feeding duty. No comfort nursing. More available positions. You may be able to see your child more fully without the breast in the way. You know exactly how much your child eats. It's easy to add vitamins or medicine to the bottle. Less likely to have foremilk/hindmilk imbalance issues. You miss out on the sensation of nursing which some women don't enjoy. No trying to get proper latch from a wailing child.

Downside: Baby may overeat since the milk flows more freely from a bottle than a breast. Baby misses out on skin to skin contact unless you make a conscious effort to provide it. Babies ingest more gas when bottle feeding. You miss out on the sensation of nursing which some women enjoy. It's unknown how carefully-handled, pumped milk compares to nursed milk, but shaking damages pumped milk and freezing also destroys some of its benefits. You have bottles to clean and sterilize.

Costs:

Upside: You don't have to buy clothing suitable for nursing in public or modesty covers.

Downside: You need to buy bottles, a pump, pump parts, and milk storage containers. There are costs associated with washing/sterilizing all the pieces. You may want to buy clothing associated with pumping such as a handsfree bra.

Space:

Upside: None.

Downside: You need room for the pump, all the pieces, and all the bottle parts.

Time: This aspect depends heavily on your particular situation. How well your child eats off the breast vs. bottle, how efficiently the pump works, and how much support you have can swing this either direction.

Upside: The time pumping is the only part that absolutely has to be done by you. The feeding of the baby and washing/sterilizing pump and bottle parts could be done by someone else. If you can offload those components to someone else, you might end up with more available time.

Downside: The aggregate time spent pumping, feeding the baby, dealing with pumped milk, and washing/sterilizing pump and bottle parts in most cases takes more time overall than nursing a baby.

[NEllen05]

This is the best analysis of nursing and pumping I have come across on the internet. My son is now 2 months old and I have gone back and forth between exclusive nursing and exclusive pumping and now do a mixture of both, and would like to share some of my thoughts and experiences.

Out and about with baby:
I am uncomfortable breastfeeding in public places, so I prefer to pump and bring milk along with me. I have found it isn't so bad to just pump right before I leave to go somewhere. That way, I maximize the amount of time I can be out without worrying about pumping again, and I can bring the freshly-pumped milk along. Both the CDC and LLL agree that breastmilk can be kept at up to 78 degrees for at least 4 hours, and my baby is just fine with drinking room-temperature milk, so I don't have to worry about keeping it cool or warming it up. I wouldn't want my baby to be in a place that is that hot anyways, and feel comfortable keeping breastmilk out for up to 6 hours if it is cooler. Plus, if I am somewhere for even longer, it is usually somewhere that I can at least get a cup of hot water to heat up a bottle in.

Sleep:
If I can get someone else to take a turn feeding my son at night, it is WONDERFUL to be able to sleep longer, so pumping has an advantage there. If I have to feed the baby at night, I find nursing much easier for myself - it is faster and doesn't wake me up as much as pumping. I also think nursing helps my son fall back asleep more quickly.

Pumping Time:
There are a bunch of great benefits listed for pumping in this section. I do admit that my son is faster at nursing than it takes for me to pump, but I know it isn't like that for everyone. It really is great to pump so that I can have a little more freedom and am not so tied to my son's schedule. I can go somewhere for a few hours without worrying my son will get hungry, and without having to bring him along. Before I had my son I used to really enjoy relaxing at night with a glass of red wine (which is good for you), and by pumping I can drink a glass without worrying about giving my son any alcohol (I will have my glass immediately after pumping, and if my son is hungry within 2 - 3 hours of me having my drink, he gets expressed milk). Also, I feel that I can actually do more while pumping than nursing - I think it depends on the person and their nursing and pumping styles and comfort as far as what multitasking you can do with each. Pumping is definitely less efficient than nursing, so you have to practice a lot more self-discipline to keep your supply up, but it is definitely possible. Constantly cleaning pump parts and bottles is a huge pain.

Feeding Time:
Again, it is definitely nice to not be completely controlled by my son's schedule. I think it has really helped me be less stressed. And pumping is going to become absolutely necessary once I return to work. That's why I started exclusively pumping for a while - I was terrified my son would start refusing bottles if I nursed him. A coworker of mine had this problem, and her daughter wouldn't eat while she was at work, so her daughter changed her eating schedule to do all her feedings in the evening and throughout the night, which was exhausting to the mother. I switched back to a mixture of pumping and nursing because it was more convenient to nurse at night, and I missed the bonding time that nursing gave us. I have also found "comfort nursing" to be a great tool to use when my son seems inconsolably upset. Perhaps I shouldn't be comfort nursing him during these times, but I do and it works miracles.

I have searched the internet a lot for if there are actually any nutritional advantages to nursing that bottlefeeding breastmilk doesn't provide. A lot of people will say that nursing has nutritional advantages without going into detail or citing sources. To me, it makes sense that freezing breastmilk kills some of its leukocytes (the live cells that transfer immunity from you to your baby), and maybe some are killed or lost (by sticking to the sides of containers) by storing in the fridge, but I would assume most exclusive pumpers don't freeze all the milk they give to their babies. I am freezing milk to extend the amount of time my son will get breastmilk. I hope to start trying for a second child when my son is a year old, and will give him frozen milk during my second pregnancy.

As far as shaking breast milk goes, I have my doubts about how much that damages (or further damages) expressed milk. While my search hasn't been exhaustive, so far every mention I've found online of "shaking breast milk is bad" is referring to the same article:
"Don't Shake the Milk" by Linda J. Smith, BSE, FACCE, IBCLC
I am not a microbiology major, so I can't challenge this article, but I really wish she would have cited a scientific study or two to back up what this article says. I haven't been able to find specific studies that analyze how much shaking denatures the healthy stuff in breast milk, but my search for "denaturing molecules by shaking" came up with a few papers that indeed say shaking can denature molecules, but it seem to vary greatly depending on the type of molecule and amount and force of shaking. This makes me wonder if perhaps the "shaking breastmilk denatures molecules" conclusion might have been reached by shaking the milk very violently for hours, similarly to how "X causes cancer because feeding eleventy-billion pounds of it to a mouse gave the mouse cancer".
Plus, I find it hard to believe that the amount of shaking I do to remix separated milk is more violent than what my milk goes through when I pump - my milk comes out with such force that I can hear it hit the back of the pump before it falls down into the container. It also makes me wonder how much "shaking" breast milk experiences just by nursing... so I would assume if you gently shake or swirl your milk to mix it, it should be just fine. That's my unscientific opinion, of course

On a final note about nursing vs pumping, when I was pregnant and planned to exclusively pump, when I would tell people that (because they would ask as if it was their business), I often felt judged and looked upon as if I was making a poor decision. It really isn't anyone else's business. You have to do what will work best for you, and not worry about what other people think.