Correct Answer: A

Rationale: The most appropriate nursing diagnosis for a woman experiencing severe preeclampsia is 'Risk for injury to mother and fetus, related to central nervous system (CNS) irritability.' Severe preeclampsia poses a significant risk of injury to both the mother and the fetus due to complications such as seizures, stroke, and placental abruption. 'Risk for altered gas exchange' is not the priority diagnosis as pulmonary edema is more common in severe preeclampsia. 'Risk for deficient fluid volume' is incorrect as sodium retention in severe preeclampsia often leads to fluid overload. 'Risk for increased cardiac output' is also incorrect as antihypertensive drugs are used to reduce cardiac output in this condition.

Correct Answer: A

Rationale: Mothers usually feel the first fetal movements, known as 'quickening,' around the 18th to 20th week of pregnancy. Feeling fetal movements during the first month is unlikely and uncommon. Therefore, option B is incorrect. Options C and D are also incorrect as mothers typically do feel fetal movements during pregnancy, just not during the first month.

Correct Answer: D

Rationale: The correct answer is D. The likelihood of having a child with Down's syndrome increases as the age of the parents increases, particularly the mother's age. Choice A is incorrect because Down's syndrome is caused by an extra copy of chromosome 21, not a defect in the sex chromosomes. Choice B is incorrect as the symptoms of Down's syndrome and sickle-cell anemia are different. Choice C is also incorrect as Down's syndrome is not caused by a sexually transmitted infection during conception.

Correct Answer: C

Rationale: A sodium level of 110 mEq/L is critically low and can indicate severe dehydration and electrolyte imbalance, requiring immediate intervention.

Correct Answer: A

Rationale: Metronidazole is the correct choice for treating bacterial vaginosis as it is the first-line medication recommended for this condition. Metronidazole works by disrupting the DNA structure of bacteria, making it an effective treatment. Choice B, Fluconazole, is an antifungal medication primarily used for treating fungal infections, not bacterial vaginosis. Choice C, Acyclovir, is an antiviral medication used to treat viral infections, not bacterial vaginosis. Choice D, Clindamycin, is also used to treat bacterial infections but is not the first-line treatment for bacterial vaginosis, making it an incorrect choice in this scenario.