Lactogenesis I or Secretory Differentiation lasts from mid-pregnancy until two days postpartum.
Mammogenesis begins by the fourth or fifth week of lactation and is not fully complete until pregnancy.
Lactogenesis II or Secretory Activation is the onset of copious milk production
Galactopoiesis is the maintenance of established lactation
Wambach 2016 p 86; Wambach 2021 p 55; Core Curriculum 2013 p 289; Core Curriculum 2019 p. 93