I didn’t see any of the following within, but several halachic compilations claim women should nurse their children until the age of two (24 months)!
They quote Pischei Teshuvah 81:17, Sdei Chemed, Darkei Teshuvah 81:82, responsa Chasam Sofer Even Ha’ezer I 30, and Tzemach Tzedek Even Ha’ezer, end of 45. They also quote the Arizal saying this is true “Al pi sod”.
Nishtanu hateva’im?