World Health Organization guidelines suggest babies should be exclusively fed breastmilk up to the age of six months, and that infants are healthiest when breastfeeding continues, alongside other feeding, up to at least the age of two years. For women with full-time jobs, it’s a huge challenge—especially in places like America, where paid family leave isn’t mandated and maternity leaves are comparatively short.

Returning to the office within months or even weeks of giving birth means that nursing mothers who want to continue feeding their babies breastmilk often have only one option: regularly pumping every three to four hours (that’s how frequently babies tend to feed, so that’s the schedule breastmilk production adheres to), for as long as it takes to extract the required amount—typically 15 to 30 minutes per session.

And that’s just the start of the work to be done to make pumping successful: Pumps and bottles need to be sterilized beforehand and cleaned after, breastmilk must be refrigerated, and a designated space must be located to do the pumping. If there isn’t one available, women will have to improvise: pumping in private offices, bathrooms, and even cupboards is by no means unusual.

A new study shows that all these conditions have a material effect, and not just on women’s wellbeing. According to the research, women who aren’t supported to pump at work find themselves less able to complete their work tasks—and they produce less milk than happier, better-supported nursing mothers in the workplace.