A nurse is caring for a client who is 12 hr postpartum. Which of the following findings should alert the nurse to the possibility of a postpartum complication?

Choice A reason: Placenta previa is a condition where the placenta covers the cervix partially or completely. It can cause painless vaginal bleeding, but not abdominal pain.

Choice B reason: Prolapsed cord is a condition where the umbilical cord slips through the cervix and protrudes into the vagina or beyond. It can cause fetal distress, but not abdominal pain or vaginal bleeding.

Choice C reason: Incompetent cervix is a condition where the cervix dilates prematurely and painlessly. It can cause preterm labor and delivery, but not abdominal pain or vaginal bleeding.

Choice D reason: Abruptio placentae is a condition where the placenta separates from the uterine wall before delivery. It can cause severe abdominal pain, vaginal bleeding, and fetal distress. It is a medical emergency that requires immediate intervention.

Choice A reason: Physiological jaundice is not the correct answer, as it is a normal and benign condition that occurs in about 60% of term newborns, and usually appears after the first 24 hours of life. Physiological jaundice is caused by the breakdown of fetal hemoglobin and the immature liver function, and resolves within a few days.

Choice B reason: Maternal cocaine abuse is not the correct answer, as it is a maternal risk factor that can cause various complications in the newborn, such as low birth weight, prematurity, intrauterine growth restriction, or congenital anomalies. Maternal cocaine abuse does not cause jaundice in the newborn, unless it leads to hepatic or renal dysfunction.

Choice C reason: Maternal/newborn blood group incompatibility is the correct answer, as it is a maternal-fetal condition that can cause hemolytic disease of the newborn, which is a severe form of jaundice that can appear within the first 24 hours of life. Maternal/newborn blood group incompatibility occurs when the mother's blood type is Rh negative and the newborn's blood type is Rh positive, or when the mother's blood type is O and the newborn's blood type is A or B. The maternal antibodies cross the placenta and attack the newborn's red blood cells, causing hemolysis, anemia, and hyperbilirubinemia.

Choice D reason: Absence of vitamin K is not the correct answer, as it is a nutritional deficiency that can cause hemorrhagic disease of the newborn, which is a bleeding disorder that can occur within the first week of life. Absence of vitamin K is due to the lack of intestinal flora and the low vitamin K content in breast milk, and can cause bleeding in the skin, mucous membranes, or internal organs. Absence of vitamin K does not cause jaundice in the newborn, unless it leads to hepatic or biliary dysfunction.