With Regard to the Development of the Respiratory System,maternity Nurses

Multiple Choice

With regard to the development of the respiratory system,maternity nurses should be aware that:

A) The respiratory system does not begin developing until after the embryonic stage
B) The infant's lungs are considered mature when the L/S ratio is 1:1,at about 32 weeks
C) Maternal hypertension can reduce maternal-placental blood flow,accelerating lung maturity
D) Fetal respiratory movements are not visible on ultrasound scans until at least 16 weeks