A 3.3-kg male term infant is born via vacuum-assisted vaginal delivery to a 26-year-old G2P1001, now P2002, woman whose serology results were within normal parameters. Membranes ruptured 4 hours before delivery, and Apgar scores are 9 and 9 at 1 and 5 minutes, respectively. A hematocrit obtained shortly after birth is 46% (0.5). At 14 hours after birth, the infant has swelling around the posterior scalp that increases in size over the next 6 hours. The swelling is fluctuant and shifts with movement of the infant's head and body. The infant appears pale, and a complete blood count is obtained.
The infant's hematocrit 22 hours after birth is 12% (0.12). Skull radiographs appear normal. The infant is transfused with packed red blood cells. Coagulation studies reveal a prothrombin time of 15.8 sec, International Normalized Ratio of 1.3, and partial thromboplastin time of 60 sec. The infant is transferred to a...