Involution of uterus takes__weeks:

Uterus involutes to non pregnant size by 6 weeks. By 1 week following delivery uterus weighs around 500gm and is around 4-5 finger breadth below the umbilicus. By 2 weeks the uterus weighs about 300gm and has descended into the true pelvis and the fundus can no longer be palpated abdominally. During involution of uterus there is no loss of myometrial cells. It occurs due to diminution of size of myometrial cells as a result of enzymatic autolysis of cytoplasm. There is augmentation of protease activity. Each myometrial cell measuring about 500-800ml in late pregnancy shrinks to less than 100ml. Ref: Donald School Manual of Practical Problems in Obstetrics edited by Narendra Malhotra page 581. Maternal, Fetal, and Neonatal Physiology By Susan Tucker Blackburn