P16.16: Using ultrasound to predict fetal lung maturity (FLM): is biometry beyond 20 weeks reliable?

Abstract

The inclusion criteria was met when the patient had an amniocentesis for FLM and the first ultrasound in the records had been obtained after 20 weeks gestation. The patients were then divided into four groups (21-25, 26-30, 31-35, >35 weeks of gestation). The data was then analyzed and compared to FLM result to see if late ultrasounds could be used to help predict the outcome of FLM test. Results: A total of 997 records were available, 336 of which met criteria. The average gestational age at time of ultrasound was 33 weeks. We found that when an ultrasound was performed after 20 weeks, the FLM can be predicted with 72% sensitivity and at PPV of 62%. In addition, measurement of an AC >10th and >50th percentile, as well as BPD >50% were statistically significant parameters in predicting a mature FLM result. Conclusions: Ultrasound preformed late in pregnancy may be used to predict fetal maturity at term particularly when abdominal circumference, and biparietal diameter are evaluated. Further studies are needed to validate our findings.