This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: New born infants, Subject name: Pediatrics
[{'content': 'Foetal lung maturity is assessed by ____________ \nSelect and explain. \nA. L/S ratio, B. Billirubin content of amniotic fluid, C. Ultrasound, D. Amniocentesis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The presence of surfactant in amniotic fluid is evident of fetal lung maturity. L/S ratio determines the relative concentration of surfactant. L/S ratio is lecithin to sphingomyelin ratio and should be more than 2. There is an increased risk of respiratory distress syndrome when this ratio is less than 2. Reference : page 516 Textbook of Obstetrics Sheila Balakrishnan 2nd edition', 'role': 'assistant'}]