单选题 The uterus returns to the pelvic cavity in which time frame?
A. 7th to 9th day postpartum.
B. 2 weeks postpartum.
C. End of the 6th week postpartum.
D. When the lochia changes to alba.

【正确答案】 A

【答案解析】The normal involutional process returns the uterus to the pelvic cavity in 7 to 9 days. A significant involutional complication is the failure of the uterus to return to the pelvic cavity within the prescribed time period. This is known as subinvolution.