Cessation of breastfeeding or milk removal results in widespread alveolar rupture, subclinical inflammatory or wound-healing response, and involution throughout a woman's breasts or mammary glands. This microscopic whole-of-breast inflammatory response risks the emergence of generalised or localised clinical inflammation.1, 2

Mammary glands from mice which underwent abrupt involution exhibited higher levels of mammary gland inflammation and cell proliferation, resulting in denser stroma and altered collagen composition.3

A woman wishing to downregulate her supply or wean her infant is best doing this gradually, over a week or two at least, depending on her situation, to avoid breast inflammation as she calibrates her breasts’ response.

Often, it is kindest to wean an older child from the breast by completely ceasing breastfeeds from the appointed day of weaning onwards. In this case, a woman needs to manage her full breasts, in which alveoli are in widespread microscopic process of rupture and involution, by hand expression (or light pumping) to comfort, in order to avoid a clinical presentation of breast inflammation.

Selected references

1. Jindal S, Narasimhan J, Vorges VF, Schedin P. Characterization of weaning-induced breast involution in women: implications for young women's breast cancer. Breast Cancer. 2020;6(55):https://doi.org/10.1038/s41523-41020-00196-41523.

2. Zaragoza R, Garcia-Trevijano ER, Lluch A, Ribas G, Vina JR. Involvement of different networks in the mammary gland involution after the pregnancy/lactation cycle: implications in breast cancer. International Union of Biochemistry and Molecular Biology. 2015;67(4):227-238.

3. Basree M, Shinde N, Koivisto C. Abrupt involution induces inflammation, estrogenic signaling, and hyperplasia linking lack of breastfeeding with increased risk of breast cancer. Breast Cancer Research. 2019;21(80):https://doi.org/10.1186/s31058-31019-31163-31057.