The maternity nurse understands that vascular volume increases 40% to 45% during pregnancy to:

Choice A reason: Maternal placenta previa is not a common complication of gestational diabetes mellitus. Placenta previa is a condition in which the placenta covers the cervix, which can cause bleeding and preterm labor. The risk factors for placenta previa include previous cesarean delivery, multiple pregnancy, advanced maternal age, and smoking.

Choice B reason: Maternal hyperemesis and neonatal low birth weight are not directly related to gestational diabetes mellitus. Hyperemesis is a severe form of nausea and vomiting during pregnancy that can cause dehydration and weight loss. The causes of hyperemesis are not well understood, but it may be influenced by hormonal changes, genetic factors, and psychological factors². Neonatal low birth weight is defined as a birth weight of less than 2,500 grams, which can be caused by many factors, such as prematurity, intrauterine growth restriction, maternal infection, and maternal malnutrition.

Choice C reason: Maternal premature rupture of membranes and neonatal sepsis are not specific to gestational diabetes mellitus. Premature rupture of membranes is a condition in which the amniotic sac breaks before labor begins, which can increase the risk of infection and preterm delivery. The causes of premature rupture of membranes are not clear, but some possible factors include infection, inflammation, stress, and trauma. Neonatal sepsis is a life-threatening infection in newborns, which can be caused by bacteria, viruses, or fungi. The risk factors for neonatal sepsis include prematurity, low birth weight, maternal infection, and invasive procedures⁵.

Choice D reason: Maternal preeclampsia and fetal macrosomia are the most common and serious complications of gestational diabetes mellitus. Preeclampsia is a condition characterized by high blood pressure and protein in the urine, which can lead to organ damage, seizures, and death. The exact cause of preeclampsia is unknown, but it may be related to abnormal placental development, immune system dysfunction, and genetic factors⁶. Fetal macrosomia is a condition in which the baby is larger than normal, usually weighing more than 4,000 grams at birth. This can cause difficulties during labor and delivery, such as shoulder dystocia, birth trauma, and cesarean section. The main cause of fetal macrosomia is excessive maternal glucose, which stimulates fetal insulin production and growth.

Choice A reason: Vascular volume increases during pregnancy to meet the increased oxygen and nutrient demands of the fetus, not to compensate for decreased renal plasma flow. In fact, renal plasma flow increases by 50% to 80% during pregnancy to facilitate the excretion of metabolic wastes.

Choice B reason: Vascular volume increases during pregnancy to ensure adequate blood supply to the uterus and other organs, not to prevent maternal and fetal dehydration. Dehydration can occur due to vomiting, diarrhea, or inadequate fluid intake, and it can be prevented by drinking enough fluids and replacing electrolytes.

Choice C reason: Vascular volume increases during pregnancy to provide adequate perfusion of the placenta, which is the main organ of gas exchange and nutrient delivery for the fetus. The placenta receives about 10% of the maternal cardiac output at term.

Choice D reason: Vascular volume increases during pregnancy to support the growth and development of the fetus and the maternal tissues, not to eliminate metabolic wastes of the mother. Metabolic wastes are eliminated by the kidneys, lungs, skin, and gastrointestinal tract.