Involution of the Uterus
• The process where the pregnant uterus returns to its pre-pregnancy size.
• The uterus contracts after the expulsion of the placenta.
• The previously hypertrophied muscle cells shrink, rather than reduce in number.
• The fundus remains below the umbilicus within 24 hours of delivery, midway between the pubic symphysis and the umbilicus within 1 week postpartum, impalpable per abdomen by 2 weeks and returns to normal size by 6 weeks post-partum.
• The myometrium contracts the uterine vasculature (ischemic appearance).