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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
True about lecithin - sphingomyelin ratio is
assistant
The correct answer is  Concentration of lecithin relative to sphingomyelin begins to rise at 32 - 34 weeks. L / S ratio < 2 suggests high risk of RDS.