"Supply issues" refers to problems or difficulties in providing or supplying something, such as products, resources, or goods, which can lead to shortages or delays in meeting demand. Full definition
I had milk supply issues with my first baby and this tea really helped to boost milk production. (pumpables.co)
Do you think you are having milk supply issues with you're new baby? (buzzsprout.com)
I had a lot of supply issues with my son and worked really hard pumping several extra times a day to work on making enough to feed him. (mamasaywhat.com)