I returned to work when my first was 4 months old. By then, he absolutely refused to take the breastmilk in a bottle, cup, spoon, etc. I worked out this crazy arrangement with my employer to work from 7 to 3:30pm, would nurse in the morning, go back home for lunch at 11:30 (I lived about a 20' taxi ride from work) and again when I got home. He would get another feed before going to bed and one or two more in the middle of the night. I did this for about 6 months until he was doing well with his solids, but managed to nurse him until he was weaned at 17 months.