I have a 16 month old DD and went back to part time work when she was 14 months. My husband has gone part time and looks after her those three days.
I work in news journalism and have some pretty early starts (6am) some of those days and the odd weekend, but no nights (DH works 2 gruelling 14-hour news shifts in TV news) and by and large it's been fine.
At first my DH would bring my DD to work for a midday feed, but he's since phased that out and she's fine and isn't a drinker of cows milk or even that much water and seems to be fine. She makes up for it when I get home and feeds at night (we all co-sleep)
My one problem is she tends to latch on about 4.30-5.30 am so I can't extricate myself from bed to go to work if I'm on an early. So DH has basically got to read to her, try and coax he back to sleep.
Also, she's picked up on my complaining over the past year about 'tit' pain and unfortunately sometimes says it (she also says 'milk', 'booby' and 'nipple'). So I can meet DH in a crowded cafe in Canary Wharf and she can shout 'Mummy, mummy, I want TIT, give me TIT!'. Which is, needless to say, embarrassing.
Since I've been back at work I've toyed with the idea of night weaning but to be honest even though on a really bad night I've resented the pulling/pinching/on-off-all-night latching, most times I'm happy to have continued and I'm glad I have this tool to quickly reconnect, comfort and help to sleep.