What is subinvolution and how might it present?

• A. Delayed return of the uterus to its nonpregnant size; presents with prolonged lochia and a uterus that remains enlarged
• B. Rapid involution with decreased lochia
• C. Fever and chills
• D. Nausea and vomiting

Answer: (A)

Subinvolution is the delayed return of the uterus to its pre-pregnant size after delivery. After birth, the uterus normally involutes and the lochia diminishes over time; when this process is incomplete, the uterus remains enlarged and lochia stays heavier for longer than expected, which can lead to ongoing vaginal bleeding and even postpartum hemorrhage. This presentation—an enlarged uterus with prolonged lochia—best fits subinvolution. Rapid involution would shorten lochia and shrink the uterus sooner, so that does not fit. Fever and chills suggest infection such as endometritis rather than subinvolution, and nausea/vomiting are not typical signs of this condition.