A nurse is instructing a pregnant patient concerning the potential risk to her fetus from a pregnancy category B drug. What would the nurse inform the patient?

The correct answer is D. The nurse would inform the patient that animal studies have not demonstrated a risk to the fetus, but there have been no adequate studies in pregnant women. This is because Pregnancy Category B drugs have shown no adverse effects in animal studies, but there is a lack of human data. Choice A is incorrect as it implies evidence of fetal risk in humans. Choice B is incorrect because it states adverse effects in animal studies without human data. Choice C is incorrect as it claims no risk based on limited studies. Therefore, the correct answer is D as it accurately reflects the classification of Pregnancy Category B drugs.