"I wanted to ask your advice about carrying on breastfeeding and returning to work. My son is 10.5 months; I'm going back to work 3 days a week in a month's time. I usually feed him 4-5 times a day (not much at night any more thank heaven), including feeding him to sleep for bedtime and most naps. I can probably do 2-3 of those feeds once I'm working again but I'm wondering what to replace the feeds he'll miss with, and whether I can carry on feeding him more often in the days I'm with him. He's not taken to my offers of breastmilk, formula or cow's milk in a sippy cup (or bottles which he has always refused). He does drink water out of a sippy. He's been an erratic daytime feeder for ages, but to complicate things, has just started wanting to drink lots. (There's some 46-week-ish development thing I think) He eats 3 pretty decent solids meals a day too. I'm keen to carry on nursing, especially as he's small - i'm just not sure what to expect at this point, and all the extended breastfeeders I encounter seem to be SAHMs. What do you think?"
I think the things you're worrying about are going to work themselves out. But I also think there's going to be an adjustment period. As long as you know that and can work with it, you should be OK.
The biggest negative that I can think of is that he might start wanting to nurse at night again for a few weeks once you go back to work. Younger babies almost always try to make up the missed contact by nursing more at night. Your son may or may not want to nurse at night since he'll be a year old and has a better sense of object permanence, so he'll probably be better able to deal with your being gone during the day several days. But he might start waking up. If he does, it should work itself out in a few weeks once he's used to the new schedule.
I think the rest will depend on your supply and on who will be caring for him while you're at work. If your supply tends to be adequate and flexible (for example, if he nurses less one day you'll still have enough the next day), then I think you can get away with not pumping at all (especially since many women find that they can't pump enough at around 10 months, even if they still have plenty when the baby is actually nursing) and just nurse on request on the days you're home. If your supply is more tightly calibrated, you may have to pump once or twice on the days you're at work so you have enough on your off days.
If he's still nursing 2-3 times a day, then he doesn't actually need milk or a milk substitute while you're gone. He can drink water for hydration and eat for nutrition. But he may take milk (yours or cows') from a caregiver just fine even if he won't take it from you. I'd talk to the caregiver ahead of time and explain that your son won't take anything from you in any container, but that s/he's welcome to try. And then let it be the caregiver's problem. I wouldn't be surprised if your son will take milk from the caregiver easily. (Parents see this all the time on all kinds of issues, that their child won't do something for them but will do it happily for a grandparent or babysitter.) It's both annoying and liberating, because then it really isn't your problem while you're at work.
I think you're in a great spot to be going back to work. Babies this age are so stable with their nursing and eating that any disruptions you see in the first few weeks should be annoying, but minor and not worrysome. And having a 3-day schedule will mean you're still home more than you are gone, so it should be easier to maintain your grip on things at home than if you had to go straight into working 5 days a week.
Did anyone else go back when your baby was close to a year? How did it go?