<prompt> Cardiac output return to normal how many days after delivery:1 hour4 hours2 weeks4 weeks  <response>: Ans. D. 4 weeks The cardiac output CO starts to increase from 5th week of pregnancy, reaches its peak 40-50 at about 30-40 weeks. CO is lowest in the sitting or supine position and highest in the right or left lateral or knee chest position. It increases further during labor 50 and immediately following delivery 70 over the pre-labor values. Within 1-2 hours following birth, the cardiac output is estimated to be about 500mlmin and Hr 120-140min CO returns to pre labor values one hour after delivery. It returns to the pre-pregnancy level in 4 weeks time. 