Out of the 130 million annual births worldwide it is estimated that aproximately 15 million newborn infants aspirate meconium and 750000 to 1.8 million of these develop MAS. Saugstad et al, Pediatrics 1998
It occurs more frequently in infants who are postmature and small for gestational age.
Mortality rates vary between 4-12% representing approximately 30,000 to 200,000 deaths annually.
MAS occurs in approx. 35% of live births with MSAF
Obstetricians should monitor mothers at risk for uteroplacental insufficiency and fetal status in an attempt to identify fetal stress with repeated CTG and Biophysical Profile.
When meconium is detected, administering amnioinfusion with warm sterile saline may be beneficial. This procedure dilutes meconium in the amniotic fluid; therefore, the severity of aspiration may be minimized. However studies have failed to show benefit.
Timing of delivery: In pregnancies that continue past due date, induction as early as 41 wks may help prevent MAS.
Upon delivery of the head of the baby, careful suctioning of the posterior pharynx decreases the potential for aspiration of meconium.
many cases of MAS are related only to chronic hypoxia and its sequelae and cannot be prevented by efforts to clear the fetal nasopharynx of meconium.
a substantial proportion of MAS is directly caused by the meconium itself, and recommended measures to clear meconium from the fetal nasopharynx should not be abandoned on the basis of pathophysiologic considerations.
Meconium contains a high concentration of free fatty acids, lipids and bile acids which may have toxic effects on the lung.
Bile acid blockers such as cholestyramine and Albumin (serum bovine albumin) that binds to lipids and free fatty acids are administered into the trachea of the newborn infant, thereby reducing the pulmonary toxicity.
Administration may be coupled to surfactant administration.