Because after normal delivery, it takes about 42 days for the size and shape of the uterus to fully return to normal, and then you can engage in normal housework and manual labor. Before the uterus completely returns to normal, we should pay more attention to rest and avoid strenuous exercise or heavy physical labor, so as not to cause diseases such as uterine prolapse and vaginal wall bulging.
Usually confinement, about 30 days, refers to small confinement. There is not much theoretical basis, just an approximate time range. If the body recovers well, you can resume normal sexual life in about 30 days, but if you want the uterus to return to normal completely, you have to wait until 42 days later.