Final answer:
The nurse warns that alcohol and illicit drugs can cross the placental barrier, putting the fetus at risk for fetal alcohol spectrum disorders (FASD) and other developmental issues, hence the correct answer is c. cross the placental barrier. The correct option is C.
Step-by-step explanation:
When a home health nurse cautions a pregnant patient about the dangers of ingesting alcohol or illicit drugs, she is particularly concerned that these substances can cross the placental barrier. These compounds are known as teratogens, which refers to any environmental agent—biological, chemical, or physical—that causes damage to the developing embryo or fetus.
Alcohol, for instance, is known to cause a range of abnormalities termed fetal alcohol spectrum disorders (FASD), which include both physical and cognitive issues such as organ and facial malformations, developmental delays, behavioral problems, and more.
Therefore, the correct answer to the question of why a pregnant patient ingesting alcohol or illicit drugs places herself at risk and endangers her fetus is: c. cross the placental barrier.