Talk to your boss, office manager, or supervisor before you return to work. To prepare, know your rights (visit LLLI.org to see a list of your state's laws regarding pumping in the workplace), and be prepared to explain how supporting lactation in the workplace is good for your worksite as well as for you. When you have the talk, be up front and nice rather than starting by bringing up the law (which some bosses will consider a veiled threat). The best strategy is to emphasize what the workplace has to gain by supporting breastfeeding. For details, go to WomensHealth.gov for "The Business Case for Breastfeeding," newly created government materials that describe how worksite lactation support helps a company’s bottom line.
Let your boss know that you need to use your breaks to express milk for baby, and ask where you should do it. Ideally, he or she can help you make a plan. If you meet resistance, share the government booklet for managers that is part of "The Business Case for Breastfeeding" (available at WomensHealth.gov).