On d 7 postpartum , a caffeine clearance test was performed to assess liver function, following the protocol of Lakritz et al. Jugular catheters were placed and caffeine was administered intravenously as caffeine and sodium benzoate in a sterile pyrogen-free normal saline solution. Blood was collected into K EDTA- containing tubes every 30 min for 180 min and centrifuged, and the plasma was removed and stored at -20 °C until analysis. Catheters were maintained by flushing with 6 mL of sterile 3.5% sodium citrate solution following each collection. On d 21 postpartum, jugular catheters were placed for 48 h. Blood was collected as above every 8 h . to assess if a posttreatment increase (rebound) in plasma NEFA concentration occurred.