a research study is designed to assess the rate of lung maturation of preterm infants with down syndrome, by measuring the lecithin to sphingomyelin ratio (l/s ratio) in amniotic fluid, as a surrogate of adequate surfactant production. weekly amniocentesis are performed during the last trimester of pregnancy. the rate of miscarriage due to amniocentesis is estimated at one in 200 procedures. the irb determines that this procedure carries a greater than minimal risk to the fetus and that there is no direct benefit to the mother or to the fetus. which of the following is true
