Respiratory distress syndrome is common especially for infants with a__________?

Explanation

Respiratory distress syndrome is especially common in very premature infants, particularly those born before about seven months of gestation, because their lungs have insufficient surfactant. Surfactant prevents alveoli from collapsing during expiration. Students may choose less than 8 months because prematurity at that stage is also risky, but the traditional threshold used in this question is seven months.