A nurse is providing anticipatory guidance to a client who has phenylketonuria (PKU) and is planning a pregnancy. Which of the following information should the nurse include in the discussion?

"Diet sodas should not be consumed more than two or three times per week."

"Serum bilirubin should be monitored one to two times per month during pregnancy."

"Breastfeeding will prevent your baby from developing PKU."

"A low-protein diet should be followed for 3 months prior to conception."