The regressive changes during puerperium are mostly confined to the all EXCEPT:

Puerperium is the period following childbih during which the body tissues, especially the pelvic organs reve back approximately to the pre-pregnant state both anatomically and physiologically. The retrogressive changes are mostly confined to the reproductive organs with the exception of the mammary glands which in fact show features of increased activity. Involution also involves regression of all physiological changes that occurred in all body systems to return to normal to their pre-pregnant state, including, cardivascular, respiratory, urinary tract and hemodynamic changes.