In many countries of the world, there are laws that compel employers to allow nursing breaks or pumping breaks. Many of these countries also have liberal parental leave policies, so pumping or breastfeeding at work is actually not a common practice.
U.S. courts have identified breastfeeding as a privacy issue, a right that is protected from undue interference by the courts, but this concept hasn’t been used to compel an employer to allow a mother time to pump or feed her baby. However, it would be illegal to discriminate against a woman because she is breastfeeding. This means that if others in your workplace take cigarette breaks or long lunches for personal reasons, then you should be entitled to a similar break to express your milk.
Of course, as the old saying goes, “You’ll catch more flies with honey than with vinegar.” It’s better to avoid the confrontational approach. Try to see your employer’s needs and anticipate possible objections. Then be ready with answers. Look for the win-win solution and your breastfeeding-and-working career will run more smoothly.