A nurse is caring for a client who is 6 hr postpartum. The client is Rh-negative and her newborn is Rh-positive. The client asks why an indirect Coombs test was ordered by the provider. Which of the following is an appropriate response by the nurse?

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.

Choice A reason: Primigravida in spontaneous labor with preterm twins is not at the greatest risk for early postpartum hemorrhage, as preterm births are associated with lower blood loss and smaller placentas. However, this client may have other complications, such as preterm labor, premature rupture of membranes, or fetal growth restriction.

Choice B reason: Primiparous woman (G 2, P 1-0-0-1) being prepared for an emergency cesarean birth for fetal distress is not at the greatest risk for early postpartum hemorrhage, as cesarean births are associated with higher blood loss and larger incisions. However, this client may have other complications, such as infection, wound dehiscence, or thromboembolism.

Choice C reason: Multiparous woman (G 3, P 2-0-0-2) with an 8-hour labor is at the greatest risk for early postpartum hemorrhage, as multiparity and rapid labor are both risk factors for uterine atony, which is the most common cause of early postpartum hemorrhage. Uterine atony is a condition where the uterus fails to contract and retract after delivery, and can cause excessive bleeding and hypovolemic shock.

Choice D reason: Woman with severe preeclampsia on magnesium sulfate whose labor is being induced is not at the greatest risk for early postpartum hemorrhage, as preeclampsia and magnesium sulfate are both risk factors for late postpartum hemorrhage, which occurs after 24 hours of delivery. However, this client may have other complications, such as eclampsia, HELLP syndrome, or placental abruption.