A nurse teaches a pregnant woman about the presumptive, probable, and positive signs of pregnancy. The woman demonstrates an understanding of the nurse's instructions if she states that a positive sign of pregnancy is:

Choice A reason: This is not the correct answer, as the pregnant woman does not use glucose at a more rapid rate than the nonpregnant woman. In fact, the pregnant woman has lower fasting glucose levels and higher postprandial glucose levels than the nonpregnant woman. This is because the pregnant woman adapts to the increased fetal demand for glucose by increasing her insulin secretion and decreasing her hepatic glucose production.

Choice B reason: This is the correct answer, as placental hormones are antagonistic to insulin, thus resulting in insulin resistance. Insulin resistance is a condition where the cells do not respond well to insulin and require more insulin to maintain normal glucose levels. Placental hormones, such as human placental lactogen, progesterone, and cortisol, increase the insulin resistance of the maternal tissues, especially in the second and third trimesters of pregnancy. This is to ensure that the fetus has enough glucose supply, as the placenta is not insulin resistant and can transport glucose to the fetus².

Choice C reason: This is not the correct answer, as pancreatic function in the islets of Langerhans is not affected by pregnancy. The islets of Langerhans are clusters of cells in the pancreas that produce hormones, such as insulin and glucagon, that regulate glucose metabolism. Pregnancy does not impair the function of the islets of Langerhans, but rather stimulates them to increase their size and number. This is to compensate for the increased insulin resistance and glucose demand of the pregnancy.

Choice D reason: This is not the correct answer, as the pregnant woman does not increase her dietary intake significantly. The pregnant woman needs to consume adequate calories and nutrients to support the fetal growth and development, but not excessively. The recommended weight gain during pregnancy depends on the pre-pregnancy BMI of the woman, but generally ranges from 11 to 16 kg. The recommended calorie intake during pregnancy is about 300 kcal more than the pre-pregnancy intake, which is equivalent to one extra snack per day.

Choice A reason: This is incorrect because a donor embryo is not used in IVF-ET. A donor embryo is an embryo that was created from another couple's gametes and donated to an infertile couple. IVF-ET uses the couple's own gametes to create an embryo.

Choice B reason: This is incorrect because it is dismissive and unprofessional. The nurse should respect the husband's curiosity and provide accurate and clear information about the procedure. The nurse should also address any concerns or questions that the couple may have.

Choice C reason: This is correct because it is a concise and accurate description of the IVF-ET procedure. The nurse explains the main steps and the purpose of the procedure in simple terms.

Choice D reason: This is incorrect because donor sperm is not used in IVF-ET. Donor sperm is sperm that was obtained from another man and donated to an infertile couple. IVF-ET uses the husband's own sperm to fertilize the wife's eggs.