The most common cause of decreased variability in the FHR that lasts 20 minutes or less is:

Choice A rationale
While protein is essential, it is not primarily responsible for preventing anemia. Iron and folic acid play significant roles in preventing anemia by supporting red blood cell production.
Choice B rationale
Protein is crucial for fetal growth and development. It provides essential amino acids necessary for the synthesis of fetal tissues and organs, ensuring proper growth during pregnancy.
Choice C rationale
Protein intake alone does not prevent gestational diabetes. Carbohydrate metabolism and hormonal regulation are more directly related to the development and management of gestational diabetes.
Choice D rationale
Protein intake during pregnancy does not affect the development of strong teeth post-birth. Dental health is influenced by calcium, phosphorus, and other vitamins, not directly by protein consumption during pregnancy.

Choice A rationale
Quickening, the first fetal movements felt by the mother, typically occurs between 16 and 20 weeks of gestation, so she should expect to feel fluttering sensations within the next month.
Choice B rationale
At 15 weeks of gestation, it is too early for most first-time mothers to feel fetal movements. Quickening usually occurs between 16 and 20 weeks, so she has not missed the window.
Choice C rationale
While some fetal movements may be subtle, it is inaccurate to suggest that some babies are entirely quiet. Quickening is generally felt by most mothers between 16 and 20 weeks.
Choice D rationale
The baby is indeed moving, but fetal movements are usually not felt until 16 to 20 weeks of gestation in first-time pregnancies, so it is normal not to feel them yet at 15 weeks.