<qa>  What is an important biophysical test?A number of biochemical tests have been developed to predict the risk of RDS and assist obstetric care providers in delivery timing. Amniotic fluid lamellar body count LBC is an important biophysical test, based on measuring the concentration of pulmonary surfactant in amniotic fluid. It can be effectively used to assess fetal lung maturity. A noninvasive test for fetal lung maturity FLM would be useful to minimize the need for invasive testing and would be more acceptable to women. Fetal pulmonary artery Doppler waveform accelerationejection time may provide a noninvasive means of determining fetal lung maturity with relatively acceptable levels of sensitivity, specificity, and predictive values. 