The nurse is calculating the estimated date of confinement (EDC) using Nagele's rule for a client whose last menstrual period started on February 13th. Which date is most accurate?

Choice A reason: Biophysical profile is a test that assesses the fetal well-being by measuring five parameters: fetal breathing movements, fetal movements, fetal tone, amniotic fluid volume, and fetal heart rate. It does not predict chromosomal abnormalities in the fetus.

Choice B reason: Lecithin/sphingomyelin [L/S] ratio is a test that measures the amount of two phospholipids in the amniotic fluid. It is used to evaluate the fetal lung maturity and the risk of respiratory distress syndrome. It does not predict chromosomal abnormalities in the fetus.

Choice C reason: Type and crossmatch of maternal and fetal serum is a test that determines the blood type and Rh factor of the mother and the fetus. It is used to identify the risk of hemolytic disease of the newborn due to Rh incompatibility. It does not predict chromosomal abnormalities in the fetus.

Choice D reason: Multiple-marker screening is a test that measures the levels of four substances in the maternal serum: alpha-fetoprotein, human chorionic gonadotropin, unconjugated estriol, and inhibin A. It is used to estimate the risk of Down syndrome, trisomy 18, and neural tube defects in the fetus.

Choice A reason: Raising the woman's legs is not the best initial response, as it may worsen the dizziness and light-headedness. This is because raising the legs can increase the blood flow to the lower extremities and decrease the blood flow to the brain, which can cause hypotension (low blood pressure) and hypoxia (low oxygen) in the woman and the fetus.

Choice B reason: Having the woman breathe into a paper bag is not the best initial response, as it may not address the underlying cause of the dizziness and light-headedness. This technique is usually used for hyperventilation (rapid breathing), which can cause respiratory alkalosis (high blood pH) and reduce the carbon dioxide levels in the blood. However, the woman may not be hyperventilating, but rather experiencing supine hypotensive syndrome (low blood pressure when lying on the back) due to the pressure of the uterus on the inferior vena cava (a large vein that returns blood to the heart)².

Choice C reason: Turning the woman on her side is the best initial response, as it can relieve the dizziness and light-headedness by improving the blood flow to the brain and the fetus. This is because turning the woman on her side can reduce the pressure of the uterus on the inferior vena cava and increase the cardiac output (the amount of blood pumped by the heart) and the blood pressure. The left lateral position is preferred, as it can also optimize the placental perfusion (the blood flow to the placenta) and the fetal oxygenation.

Choice D reason: Assessing the woman's blood pressure and pulse is an important response, but not the first one. After turning the woman on her side, the nurse should monitor the vital signs and the fetal heart rate to evaluate the condition of the woman and the fetus. The nurse should also check for other signs and symptoms of supine hypotensive syndrome, such as nausea, sweating, and visual disturbances.