الفهرس 
Review of LiteratureOnly 14 pages are availabe for public view
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Abstract
T
he pulmonary system is considered the last fetal organ system required for extra uterine life to become functionally mature, and respiratory distress syndrome (RDS) related to pulmonary surfactant deficiency remains a major morbidity and mortality.
Some preterm deliveries are sometimes provider initiated and others can be unintentionally preterm because of gestational age (GA) errors as commonly seen in women delivered by elective caesarean section (CS)
Fetal lung maturity is the key factor for the survival of prematurely delivered newborn baby, therefore, knowledge of the fetal lung maturity is helpful to make the decision of continuation or termination of pregnancy.
Determination of fetal lung maturity traditionally was relied on amniocentesis and measurement of proteins and lipid components in the amniotic fluid.
This study was conducted with the participation of sixty pregnant women .
Ultrasound scans were performed within 48 hours prior to delivery for pregnant women from 28 weeks to 40 weeks gestational age.
The present study has shown that main pulmonary artery AT/ET ratio, fetal lung to liver echogenicity, free particles in amniotic fluid and placental grading were positively correlated with lung maturity. It identified main pulmonary artery AT/ET ratio (cutoff ≥ 0.30) with (92.3% sensitivity and 82.4% specificity), as reliable predictors of neonatal RDS. This means that fetuses who develop RDS have higher pulmonary vascular resistance, pressure, lower pulmonary blood flow and lower lung echogenicity compared with fetuses that do not develop RDS.
In the current study, we resorted to parameters that were not significantly affected by the angle of insonation; such as, main pulmonary artery AT/ET, PI and RI. There was a significant correlation between the AT/ET ratio and the development of the RDS as the AT/ET ratio was significantly lower in the RDS +ve group (mean 0.23) in comparison to the RDS -ve group (mean 0.3) (P-value 0.001). While both RI and PI showed no statistically significant difference between the two groups, P-values 0.336 and 0.271 respectively. An AT/ ET ratio cut off point of 0.3 predicted the development of neonatal RDS with a high sensitivity, specificity, negative predictive value and accuracy (92.3%, 82.4%, 93.3% and 89.8% respectively).
Also this study showed that gestational age, free particles of amniotic fluid, fetal lung to liver echogenicity and placental grading were significantly correlated with development of neonatal respiratory distress syndrome as gestational age was lower on those who eventually developed neonatal RDS (P value <0.001). so, gestational age and hence prematurity are the most important factors in neonatal RDS development.
Furthermore, combination of these parameters has greater sensitivity and negative predictive value than when either measure was used alone. Therefore, these measurements might be alternatives to invasive procedures for assessment of fetal lung maturity before delivery.
Conclusion
i
n conclusion, and based on our results, the main pulmonary artery (MPA) AT/ET ratio, together with fetal lung to liver echogenicity, free particles in amniotic fluid and placental grading can be used as non-invasive accurate methods for prediction of neonatal respiratory distress syndrome (RDS) and fetal lung maturity (FLM), with even higher sensitivity and predictive values when in-combined.
Main pulmonary artery AT/ET showed significant difference between fetuses developing RDS and those who did not, with main pulmonary artery AT/ET ratio cut off ≥ 0.30. but it is recommended to be combined to the other measurements.
Recommendations
r
esults of fetal lung maturity (FLM) tests were divided in ‘mature’ and ‘immature’ results, which is done in most studies on FLM testing, the grading of the neonatal respiratory distress syndrome (RDS) was not taken into account, which we recommend to be taken into consideration in future studies.
We recommend studying the correlation between maternal histories of steroid intake and improving fetal lung parameters more precisely in future studies regarding timing, dosage and longer interval follow up.